International Journal of Application or Innovation in Engineering & Management (IJAIEM)
Web Site: www.ijaiem.org Email: editor@ijaiem.org
Volume 3, Issue 5, May 2014
ISSN 2319 - 4847
Study of Luminescence by Laser Induced
Deposition Process for Materials with Different
Buffer Gases and Pressure
Shatha S.M. Al-azzawi
Baghdad University Physics department
Abstract
Study the fluorescence generated from the target surface of aluminum oxide, titanium dioxide when exposed to high
luminescence intensity beam of carbon dioxide laser in atmosphere of oxygen and argon gases each one separately. We found
that the intensity of the resulting fluorescence depend on the type and pressure of the gas surrounding the target in addition to the
energy density of the laser beam.
Keywords: fluorescence, aluminum oxide, titanium dioxid.
1. INTRODUCTION
Laser induced chemical vapor deposition (LICVD) is a very important technology to develop a wide range of thin films
and, crystals and electronic components, which are made of metal films, semiconductors and insulators [1-8].
This technique was used for the first time at the beginning of the seventies and since that time evolution be used not only
in heating substrate or steaming the material, but in the dissociation of gas molecules [9-18]. The study of the conditions
of the experiment other parameters is very important because they affect on the type of product in this modern way, by
focusing the laser beam on the target, the interaction of laser with the target produces plasma above the target surface
(Laser Produce Plasma) (LPP). This was an important topic of several studies because these characteristics of the plasma
are of great importance in applications of (LICVD).
This research is studied the spectrum of the fluorescence emitted from the plasma medium in the existence of different
gases (TiO2 and Al2O3) surrounding the target materials and also study the change of spectrum with changing pressure of
the gases used [20], as well as the effect of changing laser energy on that. The formation of plasma depends on the
medium in which the target present so if it is vacuum the plasma result from ionization of the steam of target material
only. However, if the surrounding medium of target a gas, so besides plasma resulting from ionized metal, there is
another plasma that resulting from ionization surrounding gas [20-25].
2. EXPERIMENT
Cell work is a cylindrical container locally manufactured material from stainless steel its length (8.3 cm) diameter (2.6
cm) has closed in both sides faced to laser beam by germanium window. The side window from which fluorescence
passes, closed by glass that allows the passage of light in the region of (UV-VIS) and prevent the passage of wavelength
(10.6 µ) for CO2 laser which occurs as a result of the dispersion of the target inside the cell, so that the laser beam falls
perpendicularly on the target.
Connecting the work cell to a vacuum system through a differential valve so that the pressure inside the cell reaches
(0.76x10-4 Torr), the cell work is also connected to the adding gas by differential valve so that it can control the pressure
of the gas accurately. Laser is focused on the sample studied by zinc solenoid lens (ZnSe) of focal length (10 cm) placed
in front of a window in a specific position. Pulsed laser energy measured by energy scale (Joul Meter) of the company
(LUMONICS Inc.) type (20D-253) this Joul Meter is one of the thermo - electric detector, which operates at room
temperature to detect the incident laser with wavelengths within the infrared region (IR), and the maximum power that
can be measured (15 J) response time (8 ms). The diameter of the aperture detector (4.6 cm) the Joul Meter connect with
oscilloscope of the company (IWATSU) type (SS-5421).
TEACO2 laser used of the company (LUMONICS Inc.) type (920 L) transversal excitation at atmospheric pressure with
good stability. Resonator of length (100 cm) consists of reflective mirror of gold – plated copper and high reflectivity (100
%) and germanium mirror with reflectivity (60 %) to get wavelength of (10.6 µ). Pulse duration of laser used is (100 ns)
repetition (1 Hz) beam divergence (10 mR). It was use of gas mixture (12% CO2, 14.3% N2, 73% He) to get energy of 3
J and less to almost 2 J as a result of many reason, including attenuation by mirrors, windows and lens used in the
experiment, as well as the result of reflection from the surface of the target.
Generated fluorescence focused on the aperture detector by a quartz lens of focal length (4 cm). The resulting
fluorescence represent the total amount of fluorescence occurring within a cell work. Specifications of the detector type
(EG and G) is shown in Table 1.
Volume 3, Issue 5, May 2014
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International Journal of Application or Innovation in Engineering & Management (IJAIEM)
Web Site: www.ijaiem.org Email: editor@ijaiem.org
Volume 3, Issue 5, May 2014
Table 1 Detector EG and G
Operating Voltage
Rising Time
Band Width
Responsetivity
Series Resistance
Peak Current
Capacitance
ISSN 2319 - 4847
Specifications
50 Volt
20 ns
350 MHz
0.6 A/W
1 KΩ
10 nA
8.5 pF
Detector circuit as shown in Figure 1.
Figure 1 Schematic diagram of the electrical detector circuit used
Detector has been connected with storage oscilloscope of company (IWATSU) type (TS-8123) and this in turn connects
with X-Y recorder of company (KIPP and ZONEN) type (BD 90). Laser energy controlled by using cylindrical
attenuation cell manufactured from material stainless steel of length (15 cm) and diameter of 3.5 cm and the cell closed
from its two ended by germanium windows (Ge) (AR/AR) this cell connects to a vacuum system. Laser energy controlled
by changing the pressure of (SF6) gas which fills the cell as shown in Figure 2.
Figure 2 Change of SF6 gas inside the attenuation cell with the changing of emerging laser energy
Gas pressure is controlled by differential valve. Pressure is measured by absolute gage of company (LYBOLD HERAES)
measures the pressure in limits (1-200 Torr). This attenuation method is characterized than other used methods. Because
of the shape of the intensity distribution of the outer laser beam is the same as the penetrating beam, unlike other
methods, where the shape is cut and this will effect significantly on the calculation of brightness intensity. The reason for
the use of (SF6) gas inside the attenuation cell is that this gas has a strong absorption lines of most of the emission band
(001-100) based on wavelength (10.6 µ) in CO2 laser.
Figure 3 represents a diagram of the experiment devices
Figure 3 Schematic diagram for the experiment devices
Volume 3, Issue 5, May 2014
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International Journal of Application or Innovation in Engineering & Management (IJAIEM)
Web Site: www.ijaiem.org Email: editor@ijaiem.org
Volume 3, Issue 5, May 2014
ISSN 2319 - 4847
3. Results
We enter oxygen and argon gases each separately in a work cell when there is aluminum oxide (Al2 O3) sample, or
titanium dioxide (TiO2) sample. We selected O2 and Ar gases, on the basis that oxygen gas is a molecular gas and
chemically active and has a susceptibility to oxidative and interaction with materials. Argon is an atomic inert gas, it does
not react with substances. Both gases are transparent to CO2 laser beam and do not have the ability to absorb laser beam.
Different pressure has been used for the two gases where the pressure of O2 gas is between 3x10-1 and 4x10-3 Torr and
pressure of Ar gas is between 3x10-1 and 7x10-3.
We draw resulting fluorescence pulse as a result of inserting of the focused laser beam by lens on the samples used in a
presence of gases under two different laser intensity, fluoridation in the presence of aluminum oxide at laser intensity 2.4
J increases gradually with the decrease in pressure of oxygen gas as in figure 4, but at the lowest intensity which is equal
to 1.2 J the fluoridation was irregular with the decrease of oxygen pressure. The resulting fluorescence when introduction
of Ar gas on aluminum oxide in the high intensity of the laser was decreased with the decrease of pressure as in figure 5.
In the low intensity it was also irregular with the decrease of argon gas pressure. Figure 6 represents the high of
fluorescence when introducing oxygen gas in a presence of titanium dioxide sample by two laser intensity equal to (1.2 –
2.6 J) the amount of fluorescence decreases gradually with decreasing pressure of oxygen gas, by introducing of argon gas
on the same sample the amount of fluorescence when using high intensity of laser decreases gradually with the decrease
of pressure, but in low intensity the fluorescence be irregular as in figure 7.
The ionization potential of argon gas higher than the ionization potential of oxygen gas, so the argon atoms surrounding
the point of interaction of laser with the target needs to have high ionization energy, therefore will not absorb a high
energy from laser in a form of expansion of the plasma so the argon gas can be considered more transparent than oxygen
gas for the laser beam.
Figure 4 Resulting fluorescence from the existence of oxygen gas around the sample of aluminium oxide in the work cell
with the change of oxygen gas pressure
Figure 5 Resulting fluorescence from the existence of argon gas around the sample of aluminium oxide in the work cell
with the change of argon pressure
Figure 6 Resulting fluorescence from the existence of oxygen gas around the sample of titanium oxide in the work cell
with the change of argon gas pressure for two laser energy
Volume 3, Issue 5, May 2014
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International Journal of Application or Innovation in Engineering & Management (IJAIEM)
Web Site: www.ijaiem.org Email: editor@ijaiem.org
Volume 3, Issue 5, May 2014
ISSN 2319 - 4847
Figure 7 Resulting fluorescence from the existence of argon gas around the sample of titanium oxide in the work cell
with the change of argon pressure for two energy
4. Discussion
We have been put the analyzer line emission on (4779.5oA) which related to the pack emission line of molecular (Al-O).
We have obtained as a result of the opposite and expected with reference [20], where the emission intensity decreased
with the presence of oxygen gas and decreased with increasing the pressure This is expected and different to what was
found by H.Sankur etal. reference [26]. While we found the situation reversed when adding argon gas was obtained with
an increase in the emission with increasing the pressure of argon gas.
We observed that the presence of gases around the target interacts with plasma that produces as a result of the bombing of
the target where the ionized that gas and ionization depends on the intensity of the light beam on the target where the
higher gets the biggest ionization happen in the surrounding gas. Explanation of this case that the first part of the laser
pulse vaporizes material from the target and generates plasma. The remaining of the pulse will be absorbed by the
surrounding ionized gas in initially form by laser induced plasma. Thus breakdown occurs in the gas and ionization
happen, but it is difficult to predict the operations that will occur accurately. In order to make sure that fluoridation is
resulting from the interaction of the plasma produced from the target with the surrounding gas and not the absorption of
the gas to the laser beam directly and breakdown in the gas happen, It has been removed the target and insert the laser
beam so ionization or fluoridation not happen then we made sure that the fluorescence is generated by the interaction of
the plasma formed from the target with the surrounding gas.
References
[1] Chiang A, Zarzycki M.H., Meuli W.P., Johnson N.M. "NMOS Logic Circuits In Laser-Crystallized Silicon On
Quyartz" Materials Research Society Symposia Proceedings V 23. Publ by North Holland New York, NY, USA and
Amsterdam, Neth P. (551-558) (1984).
[2] West, G.H., Gupta A, Beeson K.W. "Laser-Induced Chemical Vapor Deposition Of Titanium Silicide Thin Films"
Publ by Materials Research Soc, Piltsburgh, PA, USA P(124-125) (1984).
[3] Solanki Raj, Moore Cameron A, Collins George J. "Laser-Induced Chemical Vapor Deposition". Solid State
Technology V. 28 n, P. (220-227), (1985).
[4] Salathe " High Vacuum Chemical Vapor Deposition (HV-CVD) of Alumina Thin Films", THÈSE NO 4485, (2009).
[5] Bedair S.M., Whisnant J.K., Karam N.H., Tischler M.A., Katsu Yama T. "Laser Selective Deposition Of Gas On Si
Applied Physics Letters" V. 48 n, P. (174-176), (1986).
[6] Hiura Y, Uchida H., Kaneko S., Morishige Yukio, Kishida Shunji "Thin Film Transistor Using a-si:H Film
Deposited By Laser-Induced Chemical Vapor Deposition". Summ Pap Presented Conf Laser Electr Opt. Publ By
IEEE, IEEE Service Center, Piscataway, NJ, USA. Available From IFEEE Service Cent (cat n 89 CH26385)
Piscataway, NJ, USA P. (392, 394-392, 395) (1989).
[7] Arnold N., Baeuerle D. "Simulation Of Growth In Pyrolytic Laser-CVD Of Microstructures. II Two-Dimensional
Approach'. Micoelectronic Engineering V 20 n, P(43-54), (1993).
[8] Voss A., Kreutz E.W., Funken J, Alunovic M., Sung H. "Time Resolved Diagnosis Of Processes In PLD Of
Ceramics" Applied Surface Science 1985 V. 69 n, P. (174-179), (1993).
[9] Donnelly V. M., Long J., Karlicek R.F., Geva M. "Excimer Laser- nduced Deposition Of InP And Indium-Oxide
Films". Materials Research Society Symopsia Proceedings V. 29.Publ By North-Holland, New York, NY, USA And
Amsterdam, Neth, P.(73-79), (1984) .
[10] Van O. Overschelde a, Snyders b R., Wautelet a M. , "Crystallisation of TiO2 thin films induced by excimer laser
irradiation", Applied Surface Science 254, P. (971–974), (2007)
Volume 3, Issue 5, May 2014
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International Journal of Application or Innovation in Engineering & Management (IJAIEM)
Web Site: www.ijaiem.org Email: editor@ijaiem.org
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[11] West G.A., Gupta A., Besson W. "Excimer Laser-Induced Chemical Vapor Deposition Of Titanium Silicide Films".
Pupl By IEEE, New York, NY, USA. Available From IEEE Service Cent (cat n CH 2174-1 , Piscataway, NJ, USA, P.
(284-286), (1985) .
[12] Hanabusa M. "Photoinduced Deposition Of Thin Films". Mater Sci Rep V. 2 n, P. (51-97), (1987).
[13] David J. Musgraves, Potter Jr B.G., and Timothy J. Boyle, "Photo-induced Deposition of Nanostructured Thin
Films by UV-exposure of Heteroleptic Ti-alkoxide Solutions", Volume 1074 ,( 2008).
[14] Bedair S.M. "Laser-Assisted Metallo-Organic Chemical Vapor Deposition". Publ By Optical Soc Of America
Washington, DC, Piscataway, NJ, USA 1987 P. 300.
[15] Conda O., Deus A.M., Ferreira M.L.G., Silvestre A.C. "Versatile Reactor For LICVD Large Films Production"
Vacuum V. 39 n, P. (861), (1989).
[16] Zabarnick S., Fleming J.W., Lin M.C. "Kinetics Of CH Radical Reactions With N2O, SO2 , OCS2, and SF6".
International Journal Of Chemical Kinetics V. 21 n 9 Sep 1989 P. 765-774.
[17] Fantoni R., Borsella E., Piccirillo S., Nannetti C.A., Ceccato R., Enzo S. "Laser Assisted Synthesis Of Ultrafine
Silicon Power". Applied Surface Science 1985 V. 43 n, P.( 308-315), (1989).
[18] Reisse G., Gaensicke F., Ebert R., Iiimann U., Johansen H. "Laser-Induced Chemical Vapour Deposition Of
Conductive And Insulalationg Thin Films". Applied Surface Science 1985 V. 54, P.( 84-88), (1992).
[19] Marco Piazzi, Luca Croin, Ettore Vittone, and Giampiero Amato, "Laser-induced etching of few-layer graphene
synthesized by Rapid-Chemical Vapour Deposition on Cu thin films", Springerplus, ; 1(1), 52, (2012).
[20] Rozantsev V.A., Petukw M.L., Yankovskii A.A. "Effect Of Air Pressure On Laser-Plasma Spectra". J. Appl. Spect,
Vol., 47,No. 4, P. (985), (1987).
[21] Andrew J. Effenberger, Jr. and Jill R. Scott, " Effect of Atmospheric Conditions on LIBS Spectra", sensors ISSN(
1424-8220),( 2010)
[22] A. Sona. "Laser And Their Applications". Gordon And Breach Science Publishers Ltd. (1976).
[23] R.G. Evans, A.R. Bell, B.J. Mac Gowan "Numerical Studies Of Laser-driven Ablation". J. Phys. D. Appl. Phys., Vol.
15, P. (711), (1982).
[24] Nanlei Li, Yanji Hong, Jie Wu, Weijing Zhou, Jifei Ye,"Numerical study on propulsion properties of laser ablated
polymer target", Proc. SPIE 8796, 2nd International Symposium on Laser Interaction with Matter (LIMIS 2012),
879608, doi:10.1117/12.2010669, (2013).
[25] B.S. Yilbas "The Absorption Of Incident Beam During Laser Dirlling Of Metals". Optics And Laser Tech., P. (27),
(1986).
[26] H. Sankur, J.G. Nelson, A.T. Pritt, Jr., And W.J. Gunning "Plasma Luminescence Generated In Laser Evaporation
Of Dielectrics". J. Vac. Sci. Technol. A 5(1), P.(15-21), (1987).
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