Browsing by Author "Lian, Yuan-Chi"

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Suppressing the Initial Growth of Sidewall GaN by Modifying AlN-Coated Patterned Sapphire with KOH-Based Etchant
(2019-10-29)
Hsu, Wen-Yang
;
Lian, Yuan-Chi
;
Wu, Pei-Yu
;
Yong, Wei-Min
;
Sheu, Jinn-Kong
Micron-sized patterned sapphire substrates (PSSs) with an ex situ sputtered AlN nucleation layer (NL) have been used to improve the performance of GaN-based light-emitting diodes (LEDs). The growth of GaN was enhanced not only from bottom c-plane, but also from the sidewall of the micron-sized patterns. In this study, KOH solution was used to etch AlN (especially sidewall AlN) for the first time. The additional etching process is very simple. It was found that KOH etching 1 min did enhance the light output power (LOP) of LED. However, with the increase of etching time to 4 min, the LOP decreased. Besides, the effect of remained AlN on GaN growth mechanism was investigated in detail. (C) The Author(s) 2019. Published by ECS.
Suppressing the Initial Growth of Sidewall GaN by Modifying Micron-Sized Patterned Sapphire Substrate with H3PO4-Based Etchant
(2018-12-01)
Hsu, Wen-Yang
;
Lian, Yuan-Chi
;
Wu, Pei-Yu
;
Yong, Wei-Min
;
Sheu, Jinn-Kong
Micron-sized patterned sapphire substrates (PSS) are used to improve the performance of GaN-based light-emitting diodes (LEDs). However, the growth of GaN is initiated not only from the bottom c-plane but also from the sidewall of the micron-sized patterns. Therefore, the coalescence of these GaN crystals creates irregular voids. In this study, two kinds of nucleation layers (NL)ex-situ AlN NL and in-situ GaN NLwere used, and the growth of sidewall GaN was successfully suppressed in both systems by modifying the micron-sized PSS surface.