Two-dimensional (2D) semiconductors have recently attracted tremendous interest as phototransistors due to their unique optical and electronic properties. However, for monolayer phototransistors, the detectable spectral range and the light absorption efficiency are usually quite limited. Here, we demonstrate phototransistors based on a van der Waals heterostructure (vdWH) formed by zero-dimensional (0D) silicon quantum dots (SiQDs) and 2D molybdenum disulfide (MoS₂), which show high detectivity and responsivity, especially in the ultraviolet (UV) spectral range. Compared to the phototransistor based on monolayer MoS₂ alone, the SiQD/monolayer MoS₂ vdWH phototransistor exhibits 100 times improvement in detectivity (from 1.0 × 10¹² to 1.0 × 10¹⁴ cm × Hz^1/2/W) and 89 times improvement in responsivity (from 66.7 to 6.0 × 10³ A/W) at 365 nm. The enhanced detectivity and responsivity are also observed for SiQD/a few-layer MoS₂ vdWHs. Analysis and control experiments show that charge transfer across the SiQD/MoS₂ vdWH leads to a photogating effect and photogain. The high-performance SiQD/MoS₂ vdWH phototransistors hold great promise for ultrasensitive photodetection, UV-based optical communication, neuromorphic visual sensing, and in-sensor computing applications.

中文翻译：

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由硅量子点增强的高探测率紫外敏感 2D MoS2 光电晶体管


二维 （2D） 半导体由于其独特的光学和电子特性，最近作为光电晶体管引起了极大的兴趣。然而，对于单层光电晶体管，可检测的光谱范围和光吸收效率通常非常有限。在这里，我们展示了基于零维 （0D） 硅量子点 （SiQD） 和 2D 二硫化钼 （MoS₂） 形成的范德华异质结构 （vdWH） 的光电晶体管，它们显示出高探测性和响应性，尤其是在紫外 （UV） 光谱范围内。与单独基于单层 MoS₂ 的光电晶体管相比，SiQD/单层 MoS₂ vdWH 光电晶体管在 365 nm 处的探测率提高了 100 倍（从 1.0 × 10¹² 到 1.0 × 10¹⁴ cm ×^{Hz 1/2}/W），响应度提高了 89 倍（从 66.7 到 6.0 × 10³ A/W）。SiQD/几层 MoS₂ vdWHs 的探测性和响应性也得到了增强。分析和控制实验表明，SiQD/MoS₂ vdWH 上的电荷转移会导致光门效应和光增益。高性能 SiQD/MoS₂ vdWH 光电晶体管在超灵敏光探测、基于紫外的光通信、神经形态视觉传感和传感器内计算应用中前景广阔。