The Formation and Characterization of GaN Hexagonal Pyramids

Author: Shi-Ying Zhang   Xiang-Qian Xiu   Zeng-Qin Lin   Xue-Mei Hua   Zi-Li Xie   Rong Zhang   You-Dou Zheng  

Publisher: IOP Publishing

ISSN: 0256-307X

Source: Chinese Physics Letters, Vol.30, Iss.5, 2013-05, pp. : 56801-56804

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Abstract

GaN with hexagonal pyramids is fabricated using the photo-assisted electroless chemical etching method. Defective areas of the GaN substrate are selectively etched in a mixed solution of KOH and K2S2O8 under ultraviolet illumination, producing submicron-sized pyramids. Hexagonal pyramids on the etched GaN with well-defined {1011} facets and very sharp tips are formed. High-resolution x-ray diffraction shows that etched GaN with pyramids has a higher crystal quality, and micro-Raman spectra reveal a tensile stress relaxation in GaN with pyramids compared with normal GaN. The cathodoluminescence intensity of GaN after etching is significantly increased by three times, which is attributed to the reduction in the internal reflection, high-quality GaN with pyramids and the Bragg effect.