Compensation effects in GaN:Mg probed by Raman spectroscopy and photoluminescence measurements
Compensation effects in GaN:Mg probed by Raman spectroscopy and photoluminescence measurements
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DOI：
10.1063/1.4794094
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发表时间：
2013-03-14
影响因子：
3.2
通讯作者：
Sitar, Zlatko
中科院分区：
文献类型：
--
作者：
Kirste, Ronny;Hoffmann, Marc P.;Sitar, Zlatko
利用拉曼光谱和光致发光测量研究了金属有机化学气相沉积（MOCVD）生长的掺镁GaN中的补偿效应。检查应变敏感的E-2（高）模式，增加的压缩应变显示与镁浓度低于7 × 10（18）cm（-3）的样品。对于较高的Mg浓度，该应变单调减少。这种弛豫伴随着晶体质量的突然下降。发光测量揭示了一个定义良好的近带边发光与自由，施主束缚，和受体束缚激子，以及一个特征的施主受体对（DAP）发光。根据最近的结果，三个受体结合激子和供体受体对被确定。沿着应变的变化，主要的受主束缚激子和DAP发光的强烈修改被观察到。来自拉曼光谱和发光测量的结果被解释为GaN：Mg中补偿效应的指纹，从而得出以下结论：由于Mg掺杂引发的缺陷掺入引起的补偿已经在约7 × 10（18）cm（-3）的掺杂水平下影响晶体性质。由此，氮空位的产生被引入作为应变状态和近带边发光的改变的驱动力。(C)2013年美国物理学会。[http：//dx.doi.org/10.1063/1.4794094]
Compensation effects in metal organic chemical vapour deposition grown GaN doped with magnesium are investigated with Raman spectroscopy and photoluminescence measurements. Examining the strain sensitive E-2(high) mode, an increasing compressive strain is revealed for samples with Mg-concentrations lower than 7 x 10(18) cm(-3). For higher Mg-concentrations, this strain is monotonically reduced. This relaxation is accompanied by a sudden decrease in crystal quality. Luminescence measurements reveal a well defined near band edge luminescence with free, donor bound, and acceptor bound excitons as well as a characteristic donor acceptor pair (DAP) luminescence. Following recent results, three acceptor bound excitons and donor acceptor pairs are identified. Along with the change of the strain, a strong modification in the luminescence of the dominating acceptor bound exciton and DAP luminescence is observed. The results from Raman spectroscopy and luminescence measurements are interpreted as fingerprints of compensation effects in GaN:Mg leading to the conclusion that compensation due to defect incorporation triggered by Mg-doping already affects the crystal properties at doping levels of around 7 x 10(18)cm(-3). Thereby, the generation of nitrogen vacancies is introduced as the driving force for the change of the strain state and the near band edge luminescence. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4794094]