Role of n-type AlGaN layer in photoresponse mechanism for separate absorption and multiplication (SAM) GaN/AlGaN avalanche photodiode
Role of n-type AlGaN layer in photoresponse mechanism for separate absorption and multiplication (SAM) GaN/AlGaN avalanche photodiode
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DOI：
10.1007/s11082-014-0065-2
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发表时间：
2015-06
影响因子：
3
通讯作者：
Xiaodong Wang;Xiaoyao Chen;Liwei Hou;B. Wang;Wei Xie;M. Pan
中科院分区：
文献类型：
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作者：
Xiaodong Wang;Xiaoyao Chen;Liwei Hou;B. Wang;Wei Xie;M. Pan
介绍了分离吸收倍增雪崩光电二极管（APD）光谱响应特性的详细建模过程。为了验证数值模型的有效性，首先给出了不同偏差下的光响应光谱。结果表明，在不存在反向偏置的情况下，在330 ~ 360 nm波长范围内形成了一个窗口区，在240 ~ 380 nm波长范围内的响应度随着偏置的增加而显著增加。初步研究了n型AlGaN层在光响应机制中的作用。我们着重讨论了响应度分别与n型层厚度和掺杂浓度的关系。结果表明，只要n型层厚度超过50 nm，探测器的抑制比随n型层厚度呈指数增长。最后，得到了优化SAM GaN/AlGaN APD的n型层的最佳掺杂浓度。
The detailed procedure of modeling spectral responsivity characteristics for separate absorption and multiplication (SAM)avalanche photodiode (APD) is presented. In order to verify the validity of numerical models, the photoresponse spectra under different biases are first shown. It is found that a window region with wavelength range from 330 to 360 nm is formed regardless of reverse bias, and the responsivities with wavelength range from 240 to 380 nm notably increase with bias. The role of n-type AlGaN layer in the photoresponse mechanism is then primarily studied. Our discussion focuses on the dependence of responsivity on the thickness and doping concentration of n-type layer, respectively. It is demonstrated that the rejection ratio of the detector increases exponentially with the thickness of n-type layer as long as its thickness exceeds 50 nm. Finally, the optimal doping concentration of n-type layer is obtained for optimizing SAM GaN/AlGaN APD.