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UV–Vis–NIR broadband response of GaAs-based photocathode with multilayer graded-band cascade structure
Micro and Nanostructures ( IF 2.7 ) Pub Date : 2021-06-18 , DOI: 10.1016/j.spmi.2021.106957
Ziheng Wang , Yiijun Zhang , Yunsheng Qian , Shiman Li , Kaimin Zhang , Feng Shi , Hongchang Cheng , Gangcheng Jiao , Yugang Zeng

To improve the lattice matching, quantum efficiency and response range of the transmission-mode GaAs-based photocathode, a novel photocathode with multilayer graded-band cascade emission layer is proposed. The one-dimensional steady-state continuity equations and finite-difference time-domain methods are utilized to obtain the quantum efficiency and optical absorption characteristics of the proposed photocathode, respectively. The results show that, the built-in electric fields generated by the varying-composition and varying-doping structure can assist the photoelectrons generated in the sublayer itself and the front sublayers to transport towards the emitting surface and escape to the vacuum. Compared with the conventional AlGaAs/InGaAs structure, the proposed structure possesses better lattice matching and enhanced quantum efficiency in the UV and NIR wavelength range. A three-fold increase of quantum efficiency can be realized at 400 nm and the theoretical quantum efficiency at 1064 nm can reach 2%. Besides, the integral absorptivity is increased by 6.8% in the visible wavelength range, and 12.9% in the NIR wavelength range. It is found that the increase of the thickness of AlGaAs sublayer and GaAs sublayer mainly reduces the quantum efficiency in the UV–Vis wavelength range. When the InGaAs sublayer is thin enough, the increase of thickness would enhance the quantum efficiency in the NIR wavelength range and deteriorate that in the UV–Vis wavelength range. This work can contribute to the performance improvement of UV–Vis–NIR broadband GaAs-based photocathode.



中文翻译:

具有多层渐变带级联结构的 GaAs 基光电阴极的 UV-Vis-NIR 宽带响应

为了提高传输模式GaAs基光电阴极的晶格匹配、量子效率和响应范围,提出了一种具有多层渐变带级联发射层的新型光电阴极。利用一维稳态连续性方程和有限差分时域方法分别获得所提出的光电阴极的量子效率和光吸收特性。结果表明,由不同成分和不同掺杂结构产生的内建电场可以帮助子层本身和前子层中产生的光电子向发射表面传输并逃逸到真空中。与传统的 AlGaAs/InGaAs 结构相比,所提出的结构在紫外和近红外波长范围内具有更好的晶格匹配和增强的量子效率。400nm处量子效率可实现3倍提升,1064nm处理论量子效率可达2%。此外,积分吸收率在可见光波长范围内增加了 6.8%,在 NIR 波长范围内增加了 12.9%。发现AlGaAs子层和GaAs子层厚度的增加主要降低了UV-Vis波长范围内的量子效率。当 InGaAs 亚层足够薄时,厚度的增加会提高 NIR 波长范围内的量子效率,并降低 UV-Vis 波长范围内的量子效率。这项工作有助于提高 UV-Vis-NIR 宽带 GaAs 基光电阴极的性能。400nm量子效率可实现3倍提升,1064nm理论量子效率可达2%。此外,积分吸收率在可见光波长范围内增加了 6.8%,在 NIR 波长范围内增加了 12.9%。发现AlGaAs子层和GaAs子层厚度的增加主要降低了UV-Vis波长范围内的量子效率。当 InGaAs 亚层足够薄时,厚度的增加会提高 NIR 波长范围内的量子效率,并降低 UV-Vis 波长范围内的量子效率。这项工作有助于提高 UV-Vis-NIR 宽带 GaAs 基光电阴极的性能。400nm量子效率可实现3倍提升,1064nm理论量子效率可达2%。此外,积分吸收率在可见光波长范围内增加了 6.8%,在 NIR 波长范围内增加了 12.9%。发现AlGaAs子层和GaAs子层厚度的增加主要降低了UV-Vis波长范围内的量子效率。当 InGaAs 亚层足够薄时,厚度的增加会提高 NIR 波长范围内的量子效率,并降低 UV-Vis 波长范围内的量子效率。这项工作有助于提高 UV-Vis-NIR 宽带 GaAs 基光电阴极的性能。在可见光波长范围内积分吸收率增加了 6.8%,在近红外波长范围内增加了 12.9%。发现AlGaAs子层和GaAs子层厚度的增加主要降低了UV-Vis波长范围内的量子效率。当 InGaAs 亚层足够薄时,厚度的增加会提高 NIR 波长范围内的量子效率,并降低 UV-Vis 波长范围内的量子效率。这项工作有助于提高 UV-Vis-NIR 宽带 GaAs 基光电阴极的性能。在可见光波长范围内积分吸收率增加了 6.8%,在近红外波长范围内增加了 12.9%。发现AlGaAs子层和GaAs子层厚度的增加主要降低了UV-Vis波长范围内的量子效率。当 InGaAs 亚层足够薄时,厚度的增加会提高 NIR 波长范围内的量子效率,并降低 UV-Vis 波长范围内的量子效率。这项工作有助于提高 UV-Vis-NIR 宽带 GaAs 基光电阴极的性能。当 InGaAs 亚层足够薄时,厚度的增加会提高 NIR 波长范围内的量子效率,并降低 UV-Vis 波长范围内的量子效率。这项工作有助于提高 UV-Vis-NIR 宽带 GaAs 基光电阴极的性能。当 InGaAs 亚层足够薄时,厚度的增加会提高 NIR 波长范围内的量子效率,并降低 UV-Vis 波长范围内的量子效率。这项工作有助于提高 UV-Vis-NIR 宽带 GaAs 基光电阴极的性能。

更新日期:2021-06-20
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