Browsing by Author "Huang, Kai Feng"

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Annealing of defect states in reactive ion etched GaN
(2008-02-01)
Lan, Wen-How
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Huang, Kuo-Chin
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Huang, Kai Feng
;
Lin, Jia-Ching
;
Cheng, Yi-Cheng
The Al0.11Ga0.89N-based photodiodes fabricated under different annealing ambient after inductively Coupled plasma reactive ion etching process were studied. The dark current and photocurrent with different illuminated wavelengths were characterized. Higher photocurrent for the diode annealing in H-2 ambient can be observed and attributed to the defect-assisted photocurrent. This photocurrent shows a strong annealing ambient dependence and causes the shift of cutoff wavelength in the responsivity spectrum. The Surface state was characterized by the capacitance analysis with Schottky contact. (C) 2007 Elsevier Ltd. All rights reserved.
Enhancement of light output power of InGaN/GaN multiple quantum well light-emitting diodes by titanium dioxide texturing
(2008-07-01)
Huang, Kuo-Chin
;
Lan, Wen-How
;
Huang, Kai Feng
;
電子物理學系
;
Department of Electrophysics
The enhancement of external quantum efficiency in InGaN/GaN multiple quantum well (MQW) light-emitting diodes (LEDs) with a titanium dioxide (TiO(2)) textured film has been observed. The output power values of conventional and TiO(2) textured LEDs Lit an injection Current of 20 mA are 6.25 and 8 mW, respectively. The external quantum efficiencies of the conventional and TiO(2) textured LEDs at an injection Current of 20 mA are 11.5 and 14.8%, respectively. The external quantum efficiency of the TiO(2) textured LEDs Lit an injection current of 20 mA is 28% higher than that of the conventional LEDs. A higher-output-power InGaN/GaN MQW LED has been obtained by coating with a TiO(2) textured film.
Exploring the DBR superlattice effect on the thermal performance of a VECSEL with the finite element method
(2019-01-15)
Huo, Yongjun
;
Cho, Chun Yu
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Huang, Kai Feng
;
Chen, Yung Fu
;
Lee, Chin C.
The design criterion of thermal conductivity for the GaAs/AlAs distributed Bragg reflector (DBR) superlattice structure was thoroughly investigated to precisely analyze the thermal behaviors of the optically pumped vertically external cavity surface-emitting laser (VECSEL). A finite element model with detailed configuration of a VECSEL gain chip was constructed to fulfill the analysis. A 1060 nm VECSEL with different pump conditions was further demonstrated to verify the finite element analysis. At the VECSEL thermal rollover point, the analysis results show that the model with the superlattice property predicts more precise temperature values than that using a bulk composite property. It reveals that the accurate determination of the thermal conductivity of the DBR superlattice is significantly important for the VECSEL thermal analysis. (C) 2019 Optical Society of America
ICP-induced defects in GaN characterized by capacitance analysis
(2006-11-01)
Lan, Wen-How
;
Huang, Kuo-Chin
;
Huang, Kai Feng
;
電子物理學系
;
Department of Electrophysics
The defects induced by inductively coupled plasma reactive ion etching (ICP-RIE) on a Si-doped gallium nitride (GaN:Si) surface have been analyzed. According to the capacitance analysis, the interfacial states density after the ICP-etching process may be higher than 5.4 x 10(12) eV(-1) cm(-2), compared to around 1.5 x 10(11) eV(-1) cm(-2) of non-ICP-treated samples. After the ICP-etching process, three kinds of interfacial states density are observed and characterized at different annealing parameters. After the annealing process, the ICP-induced defects could be reduced more than one order of magnitude in both N-2 and H-2 ambient. The H-2 ambient shows a better behavior in removing ICP-induced defects at a temperature around 500 degrees C, and the interfacial states density around 2.2 x 10(11) eV(-1) cm(-2) can be achieved. At a temperature higher than 600 degrees C, the N-2 ambient provides a much more stable interfacial states behavior than the H-2 ambient. (c) 2006 Elsevier Ltd. All rights reserved.