TF3:
Diagnostics, Structure - Properties Relationship
Posters
TF3.1.P
HIGH RESOLUTION ELECTRON MICROSCOPY STUDIES OF
NICKEL OXIDE THIN FILMS DEPOSITED ON ITO SUBSTRATES
PREPARED BY SPRAY PYROLYSIS AND MAGNETRON
SPUTTERING.
Dwight R. Acosta and Carlos R. Magaña
Instituto de Física, UNAM, A.P. 20-364 ; 01000 México D.F.; MÉXICO
Nickel thin films were produced by DC sputtering on ITO substrates deposited in
turn over glass substrates. The ITO films were prepared by spray pyrolysis and DC
magnetron sputtering deposition methods respectively. The nickel-ITO films were studied
by cyclic voltammetry for fixed values of cycling and for different scanning velocities:
First: 100 cyles under 400 mV/min and 600 mV/min scanning speeds and then 2000
cycles at 400 and 600 mV/min respectively. Noticeable variation in electrochromic
behavior were observed: changes in voltagram hysteresis areas and in the position of
peaks for redox currents for each case were observed and for each one of the values
referred. Also for the same electrochemical parameters, several differences were observed
when the ITO substrate was prepared by spray pyrolysis and by magnetron sputtering
respectively. The glass-ITO-Nickel Oxide sandwich samples were studied by X ray
diffraction. Also scanning and transmission electron microscopy were used to determine
morphological and structural properties of nickel oxides films at different stages of
electrocemical treatments. Several nickel oxide species were generated under
electrochemical treatments and were decisive in the generation of the electrochromic
properties of our materials. The optical behavior of our films, related with electrochromic
properties were studied by spectophtometric techniques. Electron microscopy techniques
were used to detect morphological and structural variations. High resolution electron
microscopy, (HREM) and associated computational techniques were used to determine and
study at nanometer level the structure and composition of the species generated at each
stage of electrochemical attack. After cyclic voltammetry treatments, numerous structural
defects were detected by HREM in the surface small grains; the role of these defects in
electrochromic effects ared discussed in this work.
TF3.2.P
STUDY OF THE SUPERCONDUCTING MgB2 FILMS
BY ION BEAM ANALYSIS METHODS
E. Andrade1, M.F. Rocha2, Š. Chromik3, Mi. Jergel4*, Ma. Jergel4,5, C. Falcony4, V. Štrbík3
1
Instituto de Física, UNAM, México, D.F., México
2
Escuela Superior de Ingenería Mecánica y Eléctrica IPN, México, D.F., México
3
Institute of Electrical Engineering, Slovak Academy of Sciences, Bratislava, Slovakia
4
Depto. de Física, CINVESTAV-IPN, México, D.F., México
5
Institute of Physics, Slovak Academy of Sciences, Bratislava, Slovakia
Superconducting MgB2 films were prepared by sequential e-beam evaporation of
boron and magnesium on R-cut sapphire, silicon and glassy carbon substrates. The
deposition at room temperature consisted of 6 B-Mg sublayer steps alternating boron
sublayer at the substrate surface with the magnesium at the top of the film precursor of the
total thickness of 300 nm. An excess of about 25% of magnesium has been used if
compared with the stoichiometric composition. After the film precursor deposition, an insitu annealing has been performed at 615-620C at various partial pressures of argon. On
the prepared samples, the zero resistance Tc values have been measured. The film structure
has been investigated by the X-ray diffraction analysis in both, Bragg-Brentano as well as
in grazing incidence configurations.
In order to measure the MgB2 films composition profiles, several ion beam analysis
(IBA) methods were applied. A standard RBS technique is not sensitive enough to
determine the film boron concentration. On the other hand, it is well known that by using
some of nuclear reaction analyses (NRA) we may determine the concentration of the
present B and O (and/or other medium light element) with a rather good sensitiviy. The
combination of 3He and 2H beams used for RBS and NRA was wery suitable for the
elemental characterization of MgB2/Si and MgB2/sapphire samples. In order to obtain the
elemental composition profiles, the particle energy spectra produced by the samples
bombardment were analysed by using the SIMNRA simulation program. The IBA analysis
shows that some amount of oxygen is incorporated in all the MgB2 films. Also, the IBA
analysis shows Mg diffusion into substrates for all the samples.
This work has been supported by the IAEA CRP Contract No.11365/RO.
*
Corresponding author: Milan Jergel, Depto. de Física, CINVESTAV-IPN, Apdo.Postal 14-740,
07300 México, D.F., México, Tel. (+) 52 55 7477097 ext. 6142/6171; Fax (+) 52 55 7477096/7;
E-mail: mjergel@fis.cinvestav.mx
TF3.3.P
STRUCTURE AND MECHANICAL PROPERTIES OF PACVD
FLUORINATED AMORPHOUS CARBON FILMS
C.E. Bottani1, A. Lamperti1, L. Nobili2, P.M. Ossi1
1
INFM and Dipartimento di Ingegneria Nucleare, Politecnico di Milano, Via Ponzio 34/3,
20133 Milano,Italy
2
Dipartimento di Chimica, Materiali e Ingegneria Chimica “Giulio Natta”, Politecnico di
Milano, Via Mancinelli 7, 20131 Milano,Italy
Fluorinated amorphous carbon films (a–C:H:F) were grown from CF4 and C2H2 mixtures,
using a DC-PACVD reactor. Two sets of films were deposited: in the first set the CF4 flux
was varied in the range 0%÷71% of the total gas flux; in the second set the bias voltage
(Vb) was changed in the range –150 V÷ –350 V, with the gas flow ratio fixed at 33%. Film
structure was analysed by IR and Raman spectroscopies and film hardness was obtained by
micro-indentation measurements. IR spectra indicate the presence of –CFX, C=CHF and
C=CF2 groups in the films. With increasing fluorine content in films a DLC to polymer-like
structural transition occurs, as evidenced by a fluorescence background in Raman spectra
that appears at high fluorine content. All films consist of amorphous carbon as shown by
the D and G peaks in Raman spectra. The ID/IG intensity ratio increases with increasing
fluorine content in the film. This trend correlates with the decreasing hardness in higly
fluorinated films. The hardness also changes with Vb, showing a symmetrical trend with a
maximum at Vb= –250 V. The ID/IG ratio decreases with increasing hardness, showing a
minimum at Vb= –250 V, thus being correlated to the hardness trend. The mechanisms
involved in film formation are discussed, especially concerning the effects of fluorine
substitution for hydrogen.
Corresponding author:
Alessio Lamperti
Dipartimento di Ingegneria Nucleare
Politecnico di Milano
Via Ponzio, 34/3
I-20133 Milano – ITALY
Tel. + 02 2399.6350
Fax + 02 2399.6309
e-mail: alessio.lamperti@polimi.it
TF3.4.P
LIQUID METAL FILM EVOLUTION IN THE HIGH ELECTRIC
FIELD
N.V.Egorov, B.V.Yakovlev
Faculty of Applied Mathematics, St-Petersburg State University, Universitetski 28, StPetersburg, 198504, Russia
E-mail egorov@apmath.spbu.ru
A physical model is proposed for liquid metal film at the metal tip surface evolution during
the formation of thermo-field ion source (TFIS).
According to our model the liquid metal film evolution passes through some steps before
the stationary conditions are achieved. At the first stage the conditions for TFIS functioning
must be realized: 1) The surface temperature (at the tungsten tip with curvature radius 1
mcm) must be sufficient for surface melting, according to our data, it must be about 2/3 of
the bulk melting temperature. 2) Th electric field strength must be sufficient for Tailor cone
formation.
At the second stage the liquid metal protrusion is formed at the Tailor cone apex with 1 nm
curvature radius (nano0protrusion). At the third stage the explosive destruction of this
nano-protrusion takes place with plasma generation. At this stage the ions flow to the
extractor and the electrons to the emitter. As the result, the liquid metal is forced out to the
periphery and crater is formed. The new feature of our model is the electron flow pressure
the taking into account. So, the equilibrium state is achieved. The flow of film bombarding
electrons, fed with the field, thermionic, thermo-field ionization both of the liquid film
atoms and the emitted atoms. The experimental evidence of this behavior is the great
increase of the ion current as the conventional extractor is substituted with the sharp edges
extractor. These sharp edges directed toward the cathode work as field emission electron
source enhancing the electron pressure onto the liquid meal surface.
According to this physical model an adequate mathematical one is developed. The
stationary and kinetic characteristics of the liquid metal layer-metal tip are computed.
TF3.5.P
THERMOLUMINESCENCE OF ALUMINUM OXIDE THIN FILMS
SUBJECT TO ULTRAVIOLET RADIATION
L. Escobar-Alarcón a, E. Villagrán a, E. Camps a,, S. Romero a, J. E. Villarreal-Barajas a,
and P.R. González a
a
Departamento de Física, Instituto Nacional de Investigaciones Nucleares, Apartado
postal 18-1027, México DF 11801, México
The thermoluminescence (TL) properties of amorphous aluminum oxide thin films
subjected to ultraviolet (UV) irradiation are reported. Aluminum oxide thin films were
prepared by laser ablation from an Al2O3 target using a Nd: YAG laser with emission at the
fundamental line. Compositional, structural and morphological properties of the obtained
thin films as a function of the growth conditions have been studied. Experimental results
showed that amorphous, with practically stoichiometric composition, aluminum oxide thin
films were obtained, with a TL response which appears to be dependent on the ion energy
of the species that hit the substrate during the film growth. The TL response as a function of
the growth parameters has been investigated in order to improve such response.
Thermoluminescence glow curves exhibited one peak centered at 174 °C. This peak
showed good stability and 15% fading in the first 4 days after irradiation. The results
presented in this work show that it is possible to obtain materials in thin film form with
thicknesses as low as 150 nm, which exhibit TL response to UV irradiation. These results
suggest that aluminum oxide thin films are suitable for detection and monitoring of UV
light.


Corresponding author : E. Camps, Tel.;(52) 53297200, Fax.: (52) 53297332; E-mail: ecc@nuclear.inin.mx
Departamento de Física, Instituto Nacional de Investigaciones Nucleares, Apartado postal 18-1027, México
DF 11801, México
TF3.6.P
STUDY OF THE SURFACE OF MgB2 THIN FILMS BY AES AND XPS
METHODS
M.H. Farías1, Mi. Jergel2*, Ma. Jergel2,3, C. Falcony2, Š. Chromik4, V. Štrbík4
Centro de Ciencias de la Materia Condensada - UNAM, Ensenada, BC, México
2
Departamento de Física, CINVESTAV-IPN, México, D.F., México
3
Institute of Physics, Slovak Academy of Sciences, Bratislava, Slovakia
4
Institute of Electrical Engineering, Slovak Academy of Sciences, Bratislava, Slovakia
1
Superconducting MgB2 films were prepared by sequential e-beam evaporation of
boron and magnesium on R-cut sapphire, silicon (111) and (100), and carbon vitreous foil
substrates. The deposition at room temperature consisted of 6 B-Mg sublayer steps with the
magnesium at the top of the film precursor of the total thickness of about 300 nm. An
excess of 100% of volatile magnesium has been used if compared with the stoichiometric
composition. After the film precursor deposition, an in-situ annealing has been performed
at 630 oC and/or 700 oC at various partial pressures of argon. The best zero resistance Tc
values were 26 K in case of sapphire and silicon and 22 K for carbon vitreous foil
substrates.
Surface of the samples was analyzed by AES and XPS methods without any
cleaning and/or after being bombarded by low energy plasma of an electron cyclotron
resonance (ECR) system. The results indicate the presence of carbon at the surface together
with oxygen and magnesium. This carbon may be easily removed by ECR, leaving a
magnesium oxide surface depleted of boron.
*
Corresponding author: Milan Jergel, Depto. de Física, CINVESTAV-IPN, Apdo.Postal 14-740,
07300 México, D.F., México, Tel. (+) 52 55 7477097 ext. 6142/6171; Fax (+) 52 55 7477096/7;
E-mail: mjergel@fis.cinvestav.mx
TF3.7.P
EFFECTS OF SUBSTRATE AND THICKNESS ON THE
STRUCTURAL AND ELECTRICAL PROPERTIES OF Ni THIN
FILMS
A. Guittoum 1,*, A. Layadi 2 and S. Tobbeche 1
1) Centre de recherche nucléaire d'Alger, 02 Boulevard F. Fanon,
B. P. 399 Alger-Gare, Algeria
2) Faculté des sciences, Université Ferhat Abbas, Sétif 19000, Algeria
We report on the effects of the substrate and the thickness on the physical properties
of Ni thin films. Ni films with thickness ranging from 170 Å to 1070 Å have been
deposited thermally on Si(100) and Si(111) substrates and on glass. Rutherford
backscattering spectrometry, scanning electron microscopy and X-ray diffraction
experiments have been performed to study the structural properties of these samples. It is
found that all Ni films evaporated on glass and on Si(100) substrates have <100>
orientation. For the Ni films evaporated on Si(111) substrates, a change of texture from
<100> to <111> is observed as the film thickness increases. The lattice constant and grain
size are discussed as a function of substrate and thickness. Electrical properties have been
also studied using the four point method. All these results will be correlated and discussed.
*) e-mail: guittoum@comena-dz.org
TF3.8.P
HIGH-QUALITY ZnO FILMS PREPARED ON Si WAFERS BY LOWPRESSURE MO-CVD
K. Haga1, T. Suzuki1, Y. Kashiwaba1, H. Watanabe1, B. P. Zang2 and Y. Segawa2
1
2
Sendai National College of Technology, Sendai, 989-3124, Japan
Photodynamics Research Center, RIKEN, Sendai, 980-0868, Japan
High-quality ZnO films were successfully prepared on Si wafers by low pressure
MO-CVD using zinc acetylacetonate (Zn(C5H7O2)2) and oxygen. The c-axis oriented ZnO
(0002) films were grown on p-type Si wafers at a temperature of 520 C˚ with or without
ZnO buffer layers deposited by RF sputtering. The ZnO buffer layers were deposited in the
Ar and O2 gas mixture at a temperature of 250 C˚. The thickness of the buffer layer
measured with an electromechnical stylus instrument ranged from 0.004 to 0.12 µm.
Although the ZnO layer deposited by sputtering has a poor c-axis orientation, the ZnO
films by MO-CVD on the ZnO buffer layer showed a sharp X-ray diffraction (XRD) peak
at 34.4˚ corresponding to the (0002) of hexagonal ZnO. The peak intensity of XRD was
sensitively affected by the buffer layer thickness and exhibited a maximal value at a
thickness of 0.04 µm. The RHEED patterns of the films have bright spots with rotation of
crystallographic axis, but without rings. Diffraction planes of (10 1 0) , (21 3 0) and (1120)
rotated in the plane of the substrate were observed in the in-plain measurement of XRD.
Room temperature photoluminescence (PL) spectrum of all the films exhibits a
strong peak consisted of near-band edge emission at 378 nm. The green emission around
500 nm considered to be due to lattice defects in ZnO crystals was negligibly weak for the
ZnO films with the buffer layer.
Current-voltage (I-V) characteristics of the ZnO(n) /Si(p) structure were measured
by applying an electrical voltage to the bottom and top electrodes of vacuum deposited Al.
It exhibits nonlinear and rectifying I-V characteristics with a small current leakage in the
reverse direction. A dark-blue light was clearly observed on the periphery of the top Al
electrode when applying a forward bias voltage. These results are very encouraging for
achieving the development of optoelectronic devices such as LEDs with near-ultra violet
region of the spectrum

TEL: (+81)22-391-5599, FAX: (+81)22-391-6144, E-mail: haga@cc.sendai-ct.ac.jp
Address: Sendai National College of Technology, Kamiayasi, Aoba-ku, Sendai 989-3124 Japan
TF3.9.P
GROWTH OF TlBa2Ca2Cu3Ox FILMS
ON TEXTURIZED SILVER SUBSTRATES
R.T. Hernández L.1,2*, A. Morales3, L. Pérez-Arrieta2, J.L. Rosas M.3, M. Aguilar-Frutis2,
Mi. Jergel3, C. Falcony3, Ma. Jergel3,4, H. Mendoza5, G. Cabañas-Moreno5
1
UAM-Azcapotzalco, México D.F., México
2
CICATA-IPN, Miguel Hidalgo 11500, México D.F., México
3
Depto. de Física, CINVESTAV-IPN, México, D.F., México
4
Institute of Physics, Slovak Academy of Sciences, Bratislava, Slovakia
5
Depto. de Ciencia en Materiales, ESFM-IPN, México D.F., México
One of high Tc superconductors suitable for power applications (transmission of
electrical energy, various magnet systems) is the TlBa2Ca2Cu3Ox phase of the Tl-Ba-CaCu-O system because of its high irreversibility line, good intergrain connectivity and
relatively good magnetic flux pinning. In this work we present results concerning the
synthesis and characterization of Tl-1223 films grown on texturized silver substrates.
The film preparation procedure consisted of two steps. First, the Ba-Ca-Cu
precursors were deposited onto a silver tape, followed then by thallination of precursor in a
two-zone furnace. As a substrate we used silver foil with preferential grain orientation
produced by us by rolling the Ag billet with the total rate of reduction being 80 to 95%.
During the thallination process the precursors were kept at 850C and the Tl-source at
750C. A flow of O2 has also been applied.
The prepared samples were characterized so far by XRD, EDX and by SEM
methods. The results show plate-like grains of the Tl-1223 phase with a rather strong c-axis
orientation. A measurement of electrical properties (Tc, Ic) is currently on the way.
*
Corresponding author: R.T. Hernández L., UAM-Azcapotzalco, Depto. de Materiales, Av. San Pablo 180,
Col. Reynosa Tamps., Del. Azcapotzalco, 02200 México D.F., México, Tel. (+) 52 55 53189087, Fax (+) 52
55 53189475, E-mail : hlrt@correo.azc.uam.mx
TF3.10.P
MULTILEVEL MORPHOLOGICAL ANALYSIS OF
SEMICONTINUOUS AND CONTINUOUS METAL FILMS
Rudolf Hrach 1,2, Dušan Novotný 2
1
Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
2
Faculty of Education, J.E. Purkyně University, Ústí nad Labem, Czech Republic
Thin metal films deposited on dielectric substrates in initial stage of their growth
consist of individual three-dimensional islands. These islands coalesce and form first
semicontinuous and later continuous films. Image analysis of film photographs from the
transmission electron microscope can bring important information about physical
mechanisms of thin film growth.
During image analysis the methods convenient for the quantitative description of
film micrographs must be applied and the connection between obtained characteristics and
physical properties of studied films established. For discontinuous films the bilevel
micrographs are typically used and the methods of mathematical morphology for the
description of spatial distribution of objects applied.
In the case semicontinuous films the standard methods of mathematical morphology
gradually loss their applicability and for continuous films they cannot be used at all. One of
possible methods for the image analysis of such films seems to be the multilevel
morphological analysis of grey scale images. However, contrary to bilevel analysis, the
methods of the quantitative characterisation of such images must yet be invented.
In the contribution two simplified approaches of the multilevel image analysis in
thin film physics and physics of surfaces are suggested and tested by means of computer
experiment. The first approach is based on standard bilevel morphological methods and an
attempt is made to extent their range of validity to semicontinuous and continuous layers, in
the second approach the multilevel image is conversed into set of bilevel images and these
images are processed simultaneously. Besides these approaches, which are implemented as
computer programs and can be applied to experimental data, the new technique of genuine
multilevel image analysis based on gradient methods is discussed.

Corresponding author: Doc. RNDr. Dušan Novotný, CSc
Tel.: +420 47 5214417, Fax: +420 47 5212053, E-mail: novotnyd@pf.ujep.cz
Department of Physics, Faculty of Education, J.E. Purkyně University
České mládeže 8, 400 96 Ústí nad Labem, Czech Republic
TF3.11.P
HALL EFFECT IN AMORPHOUS Al-W ALLOYS
J. Ivkov1, N. Radić2, A. Tonejc3
Institute of Physics, Bijenička 46, HR-10001, Zagreb, Croatia
Rudjer Bošković Institute, Bijenička 54, P.O.B. 180, HR-10001 Zagreb, Croatia
3
Faculty of Sciences, Bijenička 32, HR-10001 Zagreb, Croatia
1
2
Thin films of amorphous AlxW100-x alloys (64<x<86) have been prepared by magnetron
codeposition of pure metals onto glass substrates. The magnitudes of Hall coefficient, RH,
measured at room temperature and at 77K are the same, up to the experimental error which
is smaller than 10-12 m3/As. However, the RH value is strongly dependent upon the alloy
composition, and, furthermore, it acquires positive values in the 64<x<76 composition
range.
The departure of Hall coefficient magnitudes from the values corresponding to the freeelectron gas/model, and its positive sign in amorphous metals are attributed/interpreted
to/through a) the effects of the electronic band hybridization and/or b) possible magnetic
contribution, i.e. to the anomalous (spontaneous) Hall effect.
It is expected that the magnitude of the anomalous Hall effect in amorphous alloys is
proportional to the square of electrical resistance. However, the value of electric resistance
of the investigated amorphous alloys noticeably (10%) changes in the examined
temperature interval (77-300 K), unlike the Hall coefficient magnitude. This way, a
significant magnetic contribution to the Hall effect in amorphous Al-W alloys is reasonably
excluded.
The importance of the electronic bands hybridization (sp-d hybridization in actual case) for
the interpretation of the measured variation of Hall coefficient is supported by a strong
concentration-dependence of the structural relaxation of Al-W alloys, observed through the
measurements of electrical resistance in a wide temperature range.
TF3.12.P
PROPERTIES OF ZnO PROCESSED BY MAGNETRON
SPUTTERING AND DOPED BY ION IMPLANTATION
V.A.Karpina1, V.I.Lazorenko1, G.V.Lashkarev1, V.D.Dobrowolski1, L.I.Kopylova1, V.A.
Baturin2, S.A. Pustovoytov2, A.Ju.Karpenko2, S.A.Eremin2 , P.M.Lytvyn3
1
Institute for Problems of Material Science, National Academy of Science of Ukraine, 3,
Krzhyzhanovsky Str., Kyiv, 03142, Ukraine
Phone: (044) 4443228; Fax: (044) 4442131; e-mail: lashk@ipms.kiev.ua
2
Institute of Applied Physics, National Academy of Science of the Ukraine, 40030 Sumy,
Ukraine.
3
Institute for Semiconductor Physics, National Academy of Science of Ukraine, 45, Nauka
Ave., Kyiv, 03028, Ukraine
The films of ZnO were deposited by RF magnetron sputtering at different partial pressure
of oxygen. The deposition was carried out at RF power 200 W, working pressure 0.5-1 Pa
and substrate temperatures within 150-300oC. The substrates were cleaned by glow
discharge after their supersonic pretreatment. Accordingly to XRD analysis the films were
polycrystalline with lattice parameter close to literature data. Atomic Force Microscopy
images were studied in tapping mode for films of various thicknesses deposited at different
technological regimes. The grain size diminishes at temperature increasing within 150300oC from 60 to 80 nm., while their hight arises in the interval 30-70 nm displaying the
tendency toward column structure. Electrical and optical properties as well as
photoconductivity of ZnO films were studied. The investigated films were dielectric ones
and had optical transparency within 65-85% at thicknesses in the interval 0.2-0.6 mkm. The
optical band gap is close to single crystal one (3.43eV). The films were undergone an
implantation of nitrogen ions as acceptor impurity. The results of electrical properties
studies of nitrogen doped samples are discussed. The attempt to control stoichiometry of
ZnO films by oxygen ion implantation was carried out. New methods for control of zinc
oxide film properties are generalized.
TF3.13.P
MAGNETIC CHARACTERIZATION OF YBCO THIN FILMS USING
LOW FREQUENCY AC SUSCEPTOMETER
Subhash C. Kashyap*, Dinesh K. Pandya and Kanwaljeet Singh
Thin Film Laboratory, Indian Institute of Technology Delhi,
Hauz Khas, New Delhi 110016, INDIA.
Low frequency ac-susceptibility measurments were made on laser ablated YBa2Cu3O7-
epitaxial thin films by using a single spiral pick-up coil ac-susceptometer developed in our
laboratory to study the role of oxygen content and weak-links on the magnetic behavior.
The measurement of χ ' and χ '' were made, in the temperature range of 15 to 100 K in the
presence of applied field in the range 0.1 to 16 mT, on as-deposited and vacuum annealed
samples. In the present paper, the observed modification of the absorption peak in the
susceptibility data is correlated with the extent of deoxygenation and presence of weaklinks in various samples. It was observed that in partially deoxygenated c-oriented thin
films the YBCO grains were coupled through weak-links due to their relative in-plane
rotation with respect to each other. These weak-links exhibit dependence on oxygen
stoichiometry. This technique has potential for adoption as an on-line characterization
technique to provide the values of Tc, ΔT, Jc
mag
and the volume fraction of the
superconducting phases in thin films.


Corresponding author *: Tel. +91-11-6591346; Fax. +91-11-6581114; E-mail: skashyap62@hotmail.com ,
skashyap@physics.iitd.ac.in
Address: Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi - 110 016,
INDIA.
TF3.14.P
MAGNETORAMAN IN NARROW-GAP QUANTUM WELLS: THE
RESONANT AND NON-RESONANT REGIMES.
V. Lopez-Richard(1), G.-Q. Hai(1), C. Trallero-Giner(2), G. E. Marques(3),
(1) - Instituto de Física de São Carlos, Universidade de São Paulo, 13560-970, São Carlos
SP, Brasil,
(2) – Departamanto de Física Teórica, Universidade de La Havana, 10400, La Havana,
Cuba,
(3) - Departamento de Física, Universidade Federal de São Carlos, 13565-905, São Carlos
SP, Brasil.
Raman scattering appears as one leading tool in the study of electronic excitations and
spin-related phenomena. In particular magneto-Raman geometries allow for the selective
activation of single-particle(SPE) or collective density excitations (CDE). A special
attention will be done to the electronic properties within the conduction subband by spinflip Raman scattering as a relevant and current research topic. Our theoretical framework is
based on the Kane-Weiler 8×8 k.p Hamiltonian model and is applied to narrow-gap
HgCdTe/CdTe heterostructures. The anomalous behavior of the conduction band g-factor
and cyclotron masses, in terms of the field and the Landau level-filling factor, can be
revealed in complementary Raman scattering geometries.
Resonant Raman scattering is effective at energies of the incident light, ħωL, above the
effective energy gap (ħωL > Eg ), creating electron-hole pairs. In order to describe the
carrier-light interaction, it is common to use the dipole approximation when we deal with
interband optical transitions.
The Raman cross-section in the non-resonant regime, ħωL < Eg , is based on the study of
the dielectric function response for narrow-gap quantum wells under a magnetic field.
Due to the strong anisotropy induced by the spatial confinement and by the magnetic field,
the response function of the system is very sensitive to the angle, θ , of the incident light
with respect to the growth direction of the sample. SPE appear as intermediary states of
back-scattering Raman processes with incident angle θ=45o and are directly related to intraLandau level transitions with spin-flip. These modes are active in a range of two
consecutive even values of the filling factor ν since they result from transitions involving
spin-split levels. The stair-like path is commanded by the abrupt Landè factor dependence
on the Landau level induced by the strong interband coupling. Spin-flip intra- and interLandau level transitions are forbidden in the limit θ→90 o since they are only effective for
finite values of the component of the momentum perpendicular to the growth direction.


Corresponding author : G. E. Marques: Phone: +55-16-260.8222, Ext: 215; Fax.: +55-16-261.4835;
E-mail: gmarques@df.ufscar.br
Departamento de Física, Universidade Federal de São Carlos, 13565-905, São Carlos SP,
Brasil.
TF3.15.P
STRUCTURE PROPERTIES OF COMPOSITE FILMS
S. Novák1, R. Hrach1,2
1
Department of Physics, J. E. Purkyně University, České mládeže 8
400 96 Ústí nad Labem, Czech Republic.
2
Faculty of Mathematics and Physics, Charles University, V Holešovičkách 2
180 00 Prague 8, Czech Republic
Thin composite films represent class of promising materials. Composite metal/dielectric
films consisting of metal particles embedded into an oxide or polymer matrix have received
more and more attention in last few years due to their interesting optical, mechanical, and
electrical properties. Knowledge about the structure of composite films of various types is
crucial for the appreciation of what properties the structure would have. The paper deals
with the possible statistical reconstruction of the three-dimensional structure when only one
two-dimensional image and some additional information are available. Computer
experiment is the basic tool for research in this field because of the complexity of the
problems solved. The survey of methods convenient for reconstruction of size and/or
spatial distribution of objects of which the composite structure consists, is done. The
models of the composite films uses usually symmetrically formed particles like spheres, in
the film. However, we wanted to find out the possibility of reconstruction in not so easy
cases when the particles in the film have more complex shape. First results of our research
in this field are presented here.
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Corresponding author *: Tel.; Fax.; E-mail: +420-47-521 44 17; +420-47-521 20 53; novaks@pf.ujep.cz
TF3.16.P
THE COMPRESSIBILITY AND THE WIGNER TRANSITION OF THE
TWO-DIMENSIONAL ELECTRON GAS
S. Orozcoa, R. M. Méndez-Morenoa and M. Morenob
a. Departamento de Física, Facultad de Ciencias, Universidad Nacional Autónoma de México,
Apartado Postal 21-092, 04021 México D. F., México.
b. Instituto de Física, Universidad Nacional Autónoma de México, Apartado Postal 20-364,
01000 México D. F, México
The discovery of a two-dimensional metal-insulator transition (MIT) has intensified the
experimental and theoretical research of the two-dimensional electron gas. Recently the
measurement of the compressibility has been considered as a detection method of the MIT. In
this work the compressibility of the system is studied in the deformable jellium model (DJM)
with the self-consistently Hartree-Fock (HF) approximation. In the DJM the background is
statically deformed in order to get local charge neutrality. This method describes in a unified
form, the properties of the system at the metallic, intermediate and low density regions, which
includes the symmetry transition from the homogeneous phase in the metallic state to the
localized phase in the insulating state. The single-particle state functions are taken as the usual
plane wave multiplied by modulating functions with hexagonal symmetry. The coefficients of
the expansion are determined self-consistently by solving the HF equations with
orthonormality condition. At high densities the solution converges to a homogeneous system.
After the transition point the solution corresponds to a localized system with a periodic
density centered on a hexagonal lattice, which at low densities approaches to the Wigner
crystal. A carefully calculation, with a great number of points, was made in the interest region
in order to obtain a state equation for the system. The coupling parameter
the ratio of the average potential energy to the average kinetic energy, is used by the
theoretical analysis as a precise criterion to determine the transition point, nevertheless the
chemical potential is the property that can be utilized in the experimental praxis to locate
precisely the critical point. Therefore the total energy (per unit area), the chemical potential
and the compressibility are calculated for the densities range near to the transition from the
fluid to the localized phase. Our results describe the qualitative behavior of the
compressibility obtained for the two-dimensional hole system in GaAs/AlGaAs
heterostructures in the metal-insulator transition.
TF3.17.P
Plasma surface interaction. Application to the growth of hydrogenated
carbon films.
M.Ouchabane, M.Aoucher and K.Henda
Centre de Développement des Technologies Avancées
Laboratoire des plasmas
Haouch Oukil BP 17 Baba Hassen Alger, Algérie

Laboratoire des couches minces et semiconducteurs,
Institut de Physique, USTHB, BP32, El Alia,
16111 Bab-ezzouar, Alger, Algérie
The growth of hydrogenated carbon films at low-pressure plasma plays an important role
relating to their large range properties such as optical or wear resistant layers or for
electronic devices. The substrate material in contact with the plasma has a great influence
on the kinetic of the deposition process and thin film properties.
In this work, deposition experiments are conducted by RF (13.56MHz) plasma deposition
from CH4 gas using a multihole cathode with diode or triode system where the substrate is
grounded or biased at different potentials. To investigate the plasma surface interaction on
the basis of macroscopic quantities such as the growth rate and film density the films are
deposited on two-substrate material with changing pressure and self-bias potential. These
are the parameters, which determine the ion bombardment energy distribution and
governing of film properties. Deposition results confirm that densities vary from polymerlike to diamond -like films. Their characterization by X ray grazing diffraction and FTIR
spectroscopy reveal the structure changes in the films obtained with and without ion
bombardment.
TF3.18.P
RADIATION RESISTANCE OF Ge-As-Se THIN FILMS
N. D. Savchenko, T. N. Shchurova, I. I. Opachko
Uzhgorod National University, Ukraine
The introduction of Ge atoms into the binary As2Se3 glass results in the nonmonotonic
changes with the concentration of a number of physical properties such as, th glass
transition temperature, the molar volume, the optical bandgap, some of the mechanical
properties, etc. The concentrational dependences of the parameters near the average
coordination number of 2.67 exhibit the features, that were related to the 2D  3D
topological structural transition [1] or to the chemical transition [2]. The behaviour of these
dependences correlates with the the average chemical bond breaking energy and is to be the
same for the films obtained from the glasses of the Ge-As-Se family. The analysis of the
correlation of the average bond breaking energy with glass transition temperature and
radiation resistance is of an interest in view of the possible applications and its results can
be used for the prediction of film behaviour in the zone of radiation.
In this work the results of the investigation of the high-energy (6.5 MeV,
M-10 microtrone) irradiation effect on the optical bandgap of thin films obtained by
thermal evaporation in vacuum of the starting bulk glasses with compositions of two
different composition lines: Gex (As2Se3)1-x (x = 0.038 - 0.167) and (GeSe2)y (As2Se3))1-y
(y = 0.4 - 0.8) 0.167), and AsSe1.86Ge0.71 , AsSeGe , AsSe3Ge, AsSe4.58Ge2.75 glasses have
been presented. For the glasses under investigation the glass transition temperature has
been determined by the differential thermal analysis method, the relative free volume and
the average bond breaking energy have been calculated theoretically. It has been found that
for thin films of the first composition line electron irradiation resulted in the the optical
bandgap decrease, when for the rest of the investigated glasses this value increased.
Interrelationships between the electron-induced changes in optical bandgap of the films and
the glass transition temperature, the average coordination number, the average bond
breaking energy and the relative free volume of bulk glasses have been analysed. Thin
films obtained from the glasses with the low average bond breaking energy, exhibit the
electron-induced decrease in optical bandgap attributed to the disordering of the structure,
when the ones obtained from the glasses with the high average bond breaking energy the
optical bandgap increases under electron irradiation due to the ordering of the film
structure. The peculiarities of the correlation of the electron-induced changes in optical
bandgap with the relative free volume have been discussed.
[1] E. R. Skordeva, D. D. Arsova . J. Non-Cryst. Solids,1995, vol. 192&193, p. 665-668.
[2] L. Tichy, H. Ticha. Philosophical Magazine B., 1999, vol. 79, No. 2, p. 373-380.
Corresponding author: Ivan I. Opachko
Uzhgorod National University, Department of Engineering, 13 Kapitulna St., Uzhgorod
88000, Ukraine, Tel./fax: +038 03122 30656
e-mail: root@tv.uzhgorod.ua
TF3.19.P
INVESTIGATION OF SUBMICROPORES IN MnO2
SEMICONDUCTOR FILMS
L.Skatkov1,* & P.Cheremskoy2
1
PCB “Argo”, 2 Kharkov National Plytechnical University
In the present report the morphology, concentration and size distribution of
submicropores (SMP) in MnO2 films obtained by thermal deposition of Mn(NO3)2
were investigated by small-angle X-ray scattering (SAXS). The observed SMP
were in the range from 0,1nm to 100 nm. We analyzed the following quantities:
type of angular distribution; asymptotics and the integral parameters of the dispersion indices of SAXS related to the typical size ln; the typical volume Vn and the
typical SMP shadow area fn.
The absence of noticeable anisotropy of SAXS shows the character of the
dispersion indices which asymptotically obey the law I(s) = s –4 ( where I(s) is the
intensity of X-ray and s is the diffraction vector ). One can assume that scattering
SMP have no domineering orientation, and they are more equiaxial than macroand micropores. However, some difference in the integral parameters ln = 5 nm,
Vn1/3 = 5 nm and fn1/2 = 13 nm allows us to conclude that SMP axes are not quite
equal. Absolute values of these parameters are close to the values calculated by the
Guinier technique based on another way of averaging pore sizes. This confirms that
most SMP have more or less equal axes, unlike macropores.
The major contribution to the SMP volume concentration is made by SMP not
exceeding 8 nm – mostly from the range from 1 nm to 8 nm. The total share of SMP
in MnO2 film is about 9,8%, which agrees with the known value.
It should be noticed that, unlike macro- and micropores, some equiaxial SMP
are closed and filled with gas. Their formation results from both clustering oxygen
vacancies shaped in MnO2 films and the fact that the solidifying rate during the
Mn(NO3)2 thermal deposition largely exceeds the gas emission rate. A part of the
emitted gas is therefore trapped in the SMP.
Poster presentation
*
Corresponding author: 4/23 Shaul ha-Melekh St., 84797 Beer Sheva, Israel.
Tel.: +972 8 6482255; Fax: +972 8 6558515; E-mail: lskatkov@surfree.net.il
TF3.20.P
IMAGE ANALYSIS IN PHYSICS – SENSITIVITY ANALYSIS OF
MORPHOLOGICAL METHODS AND THEIR APPLICATION IN
THIN FILM PHYSICS
Jiří Šimek, Rudolf Hrach
Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
In some fields of physics as in thin film physics, in solid-state physics, in
astronomy, etc., the complex systems consisting of large number of objects are being
studied. During image analysis of such systems various information can be derived –
integral characteristics describing the whole image, the size distribution of individual
objects and the spatial distribution of objects. Especially the last characteristic is very
important in physics, as the deviation of the studied system from the equilibrium state can
bring information about internal processes in the system.
The complete process of image analysis in science consists of two tasks:
– it is necessary to find convenient methods for the quantitative characterisation of studied
images,
- and it is necessary to interpret derived characteristics from the point of view of given
science.
For both these tasks the technique of computer experiment seems to be very convenient.
For the description of spatial distribution of separated objects in images (e.g. the
first stages of a Volmer-Weber mechanism of thin film growth or images in astronomy) the
methods based on the theory of mathematical morphology are commonly used. However,
most of these methods bring information in a form of more or less complex curves that are
sensitive to the technique of image preparation, therefore now the invariant numerical
features are being searched and studied in the literature.
In the contribution six both the well-known and latest morphological algorithms are
analysed, for all of them the one-number features are suggested and tested by means of
computer experiment. As input data for this analysis the simulated images generated either
by simplified soft-disk and hard-disk models or by more realistic model of metal film
growth based on the combination of molecular dynamics and Monte Carlo approaches are
used.
The results of the sensitivity analysis of morphological algorithms are applied to the
micrographs of the initial growth stages of metal films prepared on dielectric substrates.
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Corresponding author: Prof. RNDr. Rudolf Hrach, DrSc.
Tel.: +420 2 2191 2328, Fax: +420 2 8468 5095, E-mail: rudolf.hrach@mff.cuni.cz
Department of Electronics and Vacuum Physics
Faculty of Mathematics and Physics, Charles University
V Holešovičkách 2, 180 00 Prague 8, Czech Republic