Photoelectrochemical etching of epitaxial InGaN thin films: self-limited kinetics and nanostructuring
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- 作者：Xiaoyin Xiao ; xnxiao@sandia.gov" class="auth_mail" title="E-mail the corresponding author ; Arthur J. Fischer ; Michael E. Coltrin ; Ping Lu ; Daniel D. Koleske ; George T. Wang ; Ronen Polsky ; Jeffrey Y. Tsao ; jytsao@sandia.gov" class="auth_mail" title="E-mail the corresponding author
- 关键词：III-nitrides ; selective etching ; photoelectrochemical etching ; voltammetry ; quantum dots
- 刊名：Electrochimica Acta
- 出版年：2015
- 出版时间：20 April 2015
- 年：2015
- 卷：162
- 期：Complete
- 页码：163-168
- 全文大小：1941 K
文摘
We report here the characteristics of photoelectrochemical (PEC) etching of epitaxial InGaN semiconductor thin films using a narrowband laser with a linewidth less than ∼1 nm. In the initial stages of PEC etching, when the thin film is flat, characteristic voltammogram shapes are observed. At low photo-excitation rates, voltammograms are S-shaped, indicating the onset of a voltage-independent rate-limiting process associated with electron-hole-pair creation and/or annihilation. At high photo-excitation rates, voltammograms are superlinear in shape, indicating, for the voltage ranges studied here, a voltage-dependent rate-limiting process associated with surface electrochemical oxidation. As PEC etching proceeds, the thin film becomes rough at the nanoscale, and ultimately the self-limiting etch kinetics lead to an ensemble of nanoparticles. This change in InGaN film volume and morphology leads to a characteristic dependence of PEC etch rate on time: an incubation time, followed by a rise, then a peak, then a slow decay.