Hebei Key Laboratory of Optic-Electronic Information and Materials, College of Physics Science and Technology, Hebei University, Baoding 071002, P. R. China.
ACS Appl Mater Interfaces. 2023 Jun 7;15(22):26993-27001. doi: 10.1021/acsami.3c05357. Epub 2023 May 23.
BiSe, as a novel 3D topological insulator (TI), is expected to be a strong candidate for next-generation optoelectronic devices due to its intriguing optical and electrical properties. In this study, a series of BiSe films with different thicknesses of 5-40 nm were successfully prepared on planar-Si substrates and developed as self-powered light position-sensitive detectors (PSDs) by introducing lateral photovoltaic effect (LPE). It is demonstrated that the BiSe/planar-Si heterojunction shows a broad-band response range of 450-1064 nm, and the LPE response is strongly dependent on the BiSe layer thickness, which can be mainly attributed to the thickness-modulated longitudinal carrier separation and transport. The 15 nm thick PSD shows the best performance with a position sensitivity of up to 89.7 mV/mm, a nonlinearity of lower than 7%, and response time as fast as 62.6/49.4 μs. Moreover, to further enhance the LPE response, a novel BiSe/pyramid-Si heterojunction is built by constructing a nanopyramid structure for the Si substrate. Owing to the improvement of the light absorption capability in the heterojunction, the position sensitivity is largely boosted up to 178.9 mV/mm, which gets an increment of 199% as compared with that of the BiSe/planar-Si heterojunction device. At the same time, the nonlinearity is still kept within 10% as well due to the excellent conduction property of the BiSe film. In addition, an ultrafast response speed of 173/97.4 μs is also achieved in the newly proposed PSD with excellent stability and reproducibility. This result not only demonstrates the great potential of TIs in PSD but also provides a promising approach for tuning its performance.
铋硒作为一种新型的三维拓扑绝缘体（TI），由于其独特的光学和电学性质，有望成为下一代光电器件的有力候选者。在这项研究中，成功地在平面-Si 衬底上制备了一系列不同厚度为 5-40nm 的 BiSe 薄膜，并通过引入横向光伏效应（LPE）将其开发为自供电光位置敏感探测器（PSD）。结果表明，BiSe/平面-Si 异质结具有 450-1064nm 的宽响应波段，并且 LPE 响应强烈依赖于 BiSe 层厚度，这主要归因于厚度调制的纵向载流子分离和输运。15nm 厚的 PSD 表现出最佳性能，位置灵敏度高达 89.7mV/mm，非线性低于 7%，响应时间快至 62.6/49.4μs。此外，为了进一步增强 LPE 响应，通过为 Si 衬底构建纳米金字塔结构，构建了新型的 BiSe/金字塔-Si 异质结。由于异质结中光吸收能力的提高，位置灵敏度大大提高到 178.9mV/mm，与 BiSe/平面-Si 异质结器件相比，提高了 199%。同时，由于 BiSe 薄膜的优异导电性，非线性仍保持在 10%以内。此外，新提出的 PSD 还实现了 173/97.4μs 的超快速响应速度，具有出色的稳定性和可重复性。该结果不仅证明了 TIs 在 PSD 中的巨大潜力，也为调整其性能提供了一种有前途的方法。
