Conventional photodetectors (PDs) generally exhibit a unipolar photoresponse within their responsive spectral range. Different from the traditional PDs, we report here a broadband PD based on the MoS₂/GaN/Si heterojunction that shows a unique phenomenon of wavelength selectivity through photocurrent polarity inversion. Overall, the device can differentiate the photons of the ultraviolet (UV)/visible region from that of the near infrared (NIR) region. This polarity inversion is explained with the help of the band diagram and the wavelength dependent photothermoelectric (PTE) effect in MoS₂. The vertical transport characteristics of the MoS₂/GaN/Si device exhibit a high spectral response in a broad range of wavelengths (300–1100 nm) in a self-biased mode. The maximum response of the device is found to be 23.81 A/W at a wavelength of 995 nm. Our results demonstrate a route for the development of PDs without filter that possess a lot of potential for the futuristic photonic devices.

中文翻译：

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MoS2/GaN/Si 基光电探测器区分紫外/可见光子与近红外光子

传统的光电探测器 (PD) 通常在其响应光谱范围内表现出单极光响应。与传统的 PD 不同，我们在此报告了一种基于 MoS ₂ /GaN/Si 异质结的宽带 PD ，它通过光电流极性反转显示出独特的波长选择性现象。总的来说，该设备可以区分紫外 (UV)/可见光区域和近红外 (NIR) 区域的光子。借助能带图和 MoS _{2 中}的波长相关光热电 (PTE) 效应来解释这种极性反转。MoS ₂的垂直输运特性/GaN/Si 器件在自偏置模式下在很宽的波长范围 (300–1100 nm) 中表现出高光谱响应。发现该器件在 995 nm 波长下的最大响应为 23.81 A/W。我们的结果展示了一种开发无滤波器的 PD 的途径，该途径对未来光子器件具有很大的潜力。