Wang Jiaxing, Chu Chunshuang, Che Jiamang, Shao Hua, Zhang Yonghui, Sun Xiaojuan, Zhang Zi-Hui, Li Dabing
Appl Opt. 2021 Dec 10;60(35):10975-10983. doi: 10.1364/AO.445069.
Traditional GaN-based metal-semiconductor-metal (MSM) photodetector (PD) features a symmetric structure, and thus a poor lateral carrier transport can be encountered, which can decrease the photocurrent and responsivity. To improve its photoelectric performance, we propose GaN-based MSM photodetectors with an AlGaN polarization layer structure on the GaN absorption layer. By using the AlGaN polarization layer, the electric field in the metal/GaN Schottky junction can be replaced by the electric fields in the metal/AlGaN Schottky junction and the AlGaN/GaN heterojunction. The increased polarization electric field can enhance the transport for the photogenerated carriers. More importantly, such polarization electric field cannot be easily screened by free carriers, thus showing the detectability for the even stronger illumination intensity. Moreover, we also conduct in-depth parametric investigations into the impact of different designs on the photocurrent and the responsivity. Hence, device physics regarding such proposed MSM PDs has been summarized.
传统的基于氮化镓的金属-半导体-金属（MSM）光电探测器（PD）具有对称结构，因此可能会遇到横向载流子传输不佳的问题，这会降低光电流和响应度。为了提高其光电性能，我们提出了在氮化镓吸收层上具有氮化铝镓极化层结构的基于氮化镓的MSM光电探测器。通过使用氮化铝镓极化层，金属/氮化镓肖特基结中的电场可以被金属/氮化铝镓肖特基结和氮化铝镓/氮化镓异质结中的电场所取代。增加的极化电场可以增强光生载流子的传输。更重要的是，这种极化电场不容易被自由载流子屏蔽，因此对于更强的光照强度也具有探测能力。此外，我们还对不同设计对光电流和响应度的影响进行了深入的参数研究。因此，总结了有关此类提出的MSM PD的器件物理特性。
