Browsing by Author "Deng, Dongmei"

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InGaN-based light-emitting diodes grown and fabricated on nanopatterned Si substrates
(2010-05-17)
Deng, Dongmei
;
Yu, Naisen
;
Wang, Yong
;
Zou, Xinbo
;
Kuo, Hao-Chung
InGaN-based light-emitting diodes (LEDs) were grown and fabricated on nanoscale patterned Si (111) substrates (NPSi). Using anodized aluminum oxide as the etch mask, the NPSi was prepared with an average nanopore diameter of 150 nm and interpore distance of 120 nm. LEDs grown on NPSi exhibit relaxed tensile stress relative to the ones grown on microscale patterned Si (111) substrates (MPSi). Nanoheteroepitaxial lateral overgrowth was significantly promoted on NPSi, which led to extensive dislocation bending and annihilation. The devices made on NPSi exhibit lower leakage current and higher light output power as compared with those on MPSi. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3427438]
Material characteristics of InGaN based light emitting diodes grown on porous Si substrates
(2011-01-15)
Deng, Dongmei
;
Chiu, Ching-Hsueh
;
Kuo, Hao-Chung
;
Chen, Peng
;
Lau, Kei May
InGaN/GaN multiple quantum wells light emitting diodes (LEDs) with 2 mu m thick crack-free GaN buffer layers were grown on porous Si substrates by metalorganic chemical vapor deposition. The material properties of LEDs grown on porous Si were studied in comparison with LEDs grown on grid-patterned Si. The (1 0 (1) over bar 5) asymmetric reciprocal space mapping (RSM) results indicate that LEDs grown on porous Si have less lattice tilt or distortion than those grown on grid-patterned Si. Both RSM and micro-photoluminescence (micro-PL) measurements suggest that multiple quantum wells grown on porous Si are less stressed. Mechanisms behind this partial strain relaxation are discussed. (C) 2010 Elsevier B.V. All rights reserved.
Optical and electrical properties of GaN-based light emitting diodes grown on micro and nano-scale patterned Si substrate
(2011-01-01)
Chiu, Ching-Hsueh
;
Lin, Chien-Chung
;
Deng, Dongmei
;
Kuo, Hao-Chung
;
Lau, Kei-May
We investigate the optical and electrical characteristics of the GaN-based light emitting diodes (LEDs) grown on Micro and Nano-scale Patterned silicon substrate (MPLEDs and NPLEDs). The transmission electron microscopy (TEM) images reveal the suppression of threading dislocation density in InGaN/GaN structure on nano-pattern substrate due to nanoscale epitaxial lateral overgrowth (NELOG). The plan-view and cross-section cathodoluminescence (CL) mappings show less defective and more homogeneous active quantum well region growth on nano-porous substrates. From temperature dependent photoluminescence (PL) and low temperature time-resolved photoluminescence (TRPL) measurement, NPLEDs has better carrier confinement and higher radiative recombination rate than MPLEDs. In terms of device performance, NPLEDs exhibits smaller electroluminescence (EL) peak wavelength blue shift, lower reverse leakage current and decreases efficiency droop compared with the MPLEDs. These results suggest the feasibility of using NPSi for the growth of high quality and power LEDs on Si substrates.