Energy band tilt in ultra-thin InGaN film affected by the surface adsorption and desorption
Energy band tilt in ultra-thin InGaN film affected by the surface adsorption and desorption
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表面吸附和解吸对超薄InGaN薄膜能带倾斜的影响
DOI：
10.1016/j.apsusc.2018.05.015
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发表时间：
2018
影响因子：
6.7
通讯作者：
Du Guotong
中科院分区：
文献类型：
--
作者：
Liu Wei;Yang Jing;Zhao Degang;Jiang Desheng;Zhu Jianjun;Chen Ping;Liu Zongshun;Liang Feng;Liu Shuangtao;Xing Yao;Zhang Liqun;Wang Wenjie;Li Mo;Zhang Yuantao;Du Guotong
采用变温光致发光（TDPL）方法研究了InGaN超薄膜在有GaN盖层和无盖层时的发光特性。实验观察到，在一定温度下的TDPL测量中，裸InGaN薄膜的PL谱随时间的推移出现反常的衰减和红移。这可能是由于InGaN表面吸附的负电荷部分抵消了超薄InGaN薄膜中的压电场，从而使InGaN层中的量子限制Stark效应增强。然而，对于GaN覆盖的InGaN超薄膜，这些异常的光谱随时间的变化消失，因为InGaN表面上的吸附和脱附过程被GaN覆盖层屏蔽。
The luminescence characteristics of InGaN ultra-thin films with and without GaN cap layer are investigated by temperature-dependent photoluminescence (TDPL) measurements. It is experimentally observed that, during the TDPL measurements at some fixed temperatures, the PL spectra of bare InGaN film show anomalous attenuation and redshift with time passing. This may be attributable to the enhancement of quantum-confined Stark effect in InGaN layer due to the desorption of the negatively charged particles on the surface of bare InGaN film, because the adsorbed negative charges on InGaN surface partially counteract the piezoelectric field in the ultra-thin InGaN film. However, for the GaN-capped InGaN ultra-thin film, those anomalous spectral variations with time vanish, as the adsorption and desorption process on the InGaN surface are screened by the GaN cap layer.