Te-based photodetectors with the merits of low cost and CMOS-compatible fabrication process have been considered promising for broadband imaging applications. Nevertheless, the spectral response of reported devices under self-powered mode is generally limited to near-infrared wavelength below 1100 nm (corresponding to the bandgap of Si). This could be ascribed to the high room-temperature carrier density in Te and the ease of forming Type-I heterojunctions between Te and other semiconductors, which impede the effective generation and separation of photocarriers. This study reports the bandgap engineering of Te through Te-Se alloying and the fabrication of Te0.65Se0.35/Al2O3/GaAs photodiode with an extended response spectrum through ultraviolet to the short-wave infrared (SWIR) band of 1550 nm at zero bias. The effects of interface passivation on the photosensing properties were also investigated. The optimized heterojunction exhibits a pronounced photovoltaic response to 1342 nm (1550 nm) infrared light with an open-circuit voltage of ∼0.12 V (0.07 V). Particularly, the dark current density reaches a record low level of 0.1 nA/cm2 at 0 V bias, leading to a high on-off current ratio of 4.5×104 and detectivity of 1.1×107 Jones at room temperature for 1342 nm light. Self-powered UV-Vis-SWIR broadband imaging and optical communication are realized by leveraging the favorable device performance. Our work provides a frame of reference for exploring more Te1-xSex-based photodetectors. Meanwhile, it may be combined with well-developed semiconductor processing technologies for optoelectronics integration.

中文翻译：

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自驱动型 Te0.65Se0.35/GaAs SWIR 光电二极管，光谱响应达 1.55 μm，适用于宽带成像和光通信


基于 Te 的光电探测器具有低成本和 CMOS 兼容制造工艺的优点，被认为在宽带成像应用中很有前途。然而，在自供电模式下，已报道器件的光谱响应通常仅限于 1100 nm 以下的近红外波长（对应于 Si 的带隙）。这可能归因于 Te 中的高室温载流子密度以及 Te 和其他半导体之间易于形成 I 型异质结，这阻碍了光载流子的有效产生和分离。本研究报道了通过 Te-Se 合金化对 Te 进行带隙工程以及制备 Te0.65Se0.35/Al2O3/GaAs 光电二极管，该光电二极管在零偏压下通过紫外线扩展到 1550 nm 的短波红外 （SWIR） 波段。还研究了界面钝化对光敏性能的影响。优化的异质结对 1342 nm （1550 nm） 红外光和 ∼0.12 V （0.07 V） 的开路电压表现出明显的光伏响应。特别是，在 0 V 偏置时，暗电流密度达到了 0.1 nA/cm2 的历史最低水平，因此在室温下 1342 nm 光的开关电流比高达 4.5×104，探测率为 1.1×107 Jones。利用良好的器件性能，实现了自供电的 UV-Vis-SWIR 宽带成像和光通信。我们的工作为探索更多基于 Te1-xSex 的光电探测器提供了一个参考框架。同时，它可以与成熟的半导体加工技术相结合，以实现光电子集成。