No.
Technique
1
Research for Novel LED Fabrication
This study presents a substantial enhancement in electroluminescence
achieved by depositing Ag nanoparticles on an ITO-coated glass substrate
(Ag/ITO) for approximately 10-s to form novel window materials for use in
polymer light-emitting diodes (PLEDs). In addition to its low cost, this
Specification novel fabrication method can effectively increase the charge transport
properties of the active layer to meet the high performance requirements of
PLEDs. Due to the increased conductivity and work function of the Ag/ITO
substrate, the electroluminescence intensity was increased by nearly
3.3-fold compared with that of the same PLED with a bare ITO substrate.
標準 PLED
新型 PLED
Illustration
Holder /
Dep.
Tel. / E-Mail
Sy-Chann Chen/ Department of Electrophysics
2717992/shchen@mail.ncyu.edu.tw
No.
Technique
2
Research for the improved electro-optical properties of OLEDs using the
inorganic buffer layers
Li2CO3, Na2CO3 and LiOH are used as an n-type dopant to improve the
electro-optical properties of the organic light-emitting diodes (OLEDs).
Because the mobility of electrons is much lower than that of holes in
organic materials, the electron injection and transport ability must be
improved to obtain a better charge balance in an OLED. The commonly
used strategy for electron injection into an electron transport layer is to
insert a low-work-function buffer layer between an Al cathode and an Alq3
Specification
layer. However, these approaches are difficult because the material is
highly reactive to being oxidized and highly diffusive in an organic matrix,
which causes the quenching of excitons in the emission layer. In the present
work, we report the effect of the inorganic n-type dopant doped into the
Alq3 layer for OLED applications, which overcomes the exciton-quenching
problem. As can be seen from the J-V-L characteristics, the turn-voltage of
OLEDs with inorganic buffer layers is less than 3.0 V, and the luminance
and efficiency are higher than 104 cd/m2 and 5.0 %, respectively, which are
better than the results of the LiF-based devices.
Illustration
Holder /
Dep.
Tel. / E-Mail
Po-Ching Kao/ Department of Electrophysics
271-7416/pckao@mail.ncyu.edu.tw
No.
Technique
3
Surface-plasmon-enhanced silicon-base solar cell
A pyramid structure etched with KOH solution was employed on a silicon
(Si) surface to increase the absorbing path length of light; subsequently gold
(Au) nanoparticles (NPs) were deposited on the etched surface to fabricate
p-n junction solar cell using spin-on diffusion (SOD) method. Solar cells
with and without KOH etching or Au NPs were fabricated to study the
effects of KOH etching and Au NPs on the characteristics of solar cells.
Due to the larger surface area etched by KOH, more Au NPs adhere to the
Specification Si surface, and hence more surface plasmon oscillations are induced by the
incident light. For the incident wavelength longer than the oscillation
wavelength of Au NPs (550 nm), constructive interference occurs which
enhances the short-circuit current density and conversion efficiency. In
contrast, for a wavelength smaller than 550 nm, absorption dominates the
extinction spectra. The short-circuit current density and conversion
efficiency increase by 26.8% and 28.5%, respectively, compared to the
solar cells without KOH etching and without Au NPs.
Illustration
η=10.05%
η=9.06%
Holder /
Dep.
Jun-Dar Hwang/ Department of Electrophysics
05-2717958 / jundar@mail.ncyu.edu.tw
Tel. / E-Mail
No.
4
Transparent ohmic contact of indium tin oxide to n-type GaN (Taiwan
Technique
patent I288434)
A novel transparent indium tin oxide (ITO) ohmic contact to n-type GaN
(dopant concentration of 2x1017cm-3) with a specific contact resistance
of 4.2x10-6   cm2 has been obtained. The interfacial properties
involving with ITO to n-GaN ohmic contact are different from those of
previous reported. Conventionally, ITO films were prepared using
electron-beam evaporator and a Schottky contact was thereafter
obtained with a barrier height of 0.68 eV. Moreover, the barrier heights
Specification
increased in response to the rise of annealing temperature. However, in
our studies we relied on different deposition technique instead by
sputtering the ITO films onto n-type GaN using a RF sputtering system
and in result I-V curve revealed a linear behavior. By increasing the
annealing temperature to 600℃, the ohmic contact resistance appeared
to be in sharp decline. Possible explanations these phenomena were
attributed to the surface oxide layer removal and N vacancies present
on GaN surface, which occurred during the ITO sputtering.
ITO by evaporation
Illustration
ITO
ITO
n-GaN
n-GaN
I
I
V
Holder /
Dep.
Jun-Dar Hwang/ Department of Electrophysics
05-2717958 / jundar@mail.ncyu.edu.tw
Tel. / E-Mail
ITO by sputtering
V
No.
Technique
5
Transparent ohmic contact of indium tin oxide to p-type SiGe (Taiwan
patent: I297218)
Nonalloyed transparent ohmic contacts of indium tin oxide (ITO) to p-type
Si0.8Ge0.2 layer, in which the ITO films and the p-type Si0.8Ge0.2 layers were
deposited by using sputtering and ultrahigh-vacuum chemical vapor
Specification deposition (UHVCVD) system, respectively. It is shown that the ITO/
p-type Si0.8Ge0.2 contact structure exhibits a specific contact resistance as
low as 2.26x10 - 5   cm 2 as compared to that of 2.78x10-2   cm 2 for the
ITO/Si/p-type Si0.8Ge0.2 contact structure.
ITO by sputtering
I
Illustration
ITO
p-SiGe
Holder /
Dep.
Tel. / E-Mail
Jun-Dar Hwang/ Department of Electrophysics
05-2717958 / jundar@mail.ncyu.edu.tw
V
No.
Technique
Specification
6
Research for Transparent conducting Gallium-doped zinc oxide (GZO)
thin films
Transparent conducting Gallium-doped zinc oxide (GZO) thin films
have been deposited on glass substrates by pulsed laser deposition. The
structural, electrical and optical properties of these films were
investigated as a function of Ga-doping amount (0–5 wt.%) in the target.
Films were deposited at a substrate temperature of 200 °C in 20.0 m-Torr
of oxygen pressure. The properties of GZO thin films such as optical
band gap, electricitivity, microstructures and transmission were strongly
affected by Ga-doping amount. It was observed that 3.0 wt.% of Ga is the
optimum doping amount in the target to achieve the minimum film
resistivity and the maximum film transmission. For the ~200 nm thick
GZO film deposited using a ZnO target with a Ga content of 3.0 wt.%,
the electrical resistivity , concentration and mobility were 2.91x10-4
Ω-cm , 2.0x1021 cm-3 and 10.59 cm2/vs, respectively. The average
transmission of GZO thin films in the visible range (400–700 nm) was 90
%. These GZO films grown by PLD were used as transparent anodes to
fabricate the polymer light-emitting diode (PLEDs). The device
performance was measured in the GZO/PEDOT/PFO/LiF/Ca/Al diode
and a luminance of 93 cd/m2 was observed with applied voltage of 10.5V.
The intensity of electroluminescence was increased by nearly 1.4 time
compared with the PLED, which is based on an un-doped ZnO glass
substrate.
Illustration
Holder / Dep. Chang-Feng Yu/ Department of Electrophysics
Tel. / E-Mail
271-7953/ cfyu@mail.ncyu.edu.tw
No.
Technique
7
Refractive index profiling technique of optical fiber or waveguide
devices
This technique offers a creative improved refractive index profiling
method of optical fiber or waveguide devices. We focused partially
coherent laser light onto an optical fiber end-face and captured a
high-quality reflective cross-sectional image of the fiber. By analyzing
Specification the reflected light intensity distribution of the captured fiber image, we
can achieve refractive-index profiling of a step-index multimode
optical fiber. The measurement error can be deceased by proposed
ways. This simple and easy fiber-optic inspection technique is an
innovative invention of employing reduced-coherence laser light.
Illustration
Holder/ Dep. Fang-Wen Sheu / Department of Electrophysics
Tel. / E-Mail +886-5-2717993 / fwsheu@mail.ncyu.edu.tw