The two different light–matter interactions between visible and infrared light are not switchable because control mechanisms have not been elucidated so far, which restricts the effective spectral range in light-sensing devices. In this study, modulation of the effective spectral range is demonstrated using the metal–insulator transition of MoS₂. Nondegenerate MoS₂ exhibits a photoconductive effect in detecting visible light. In contrast, degenerate MoS₂ responds only to mid-infrared (not visible) light by displaying a photoinduced heating effect via free carrier absorption. Depending on the doping level, the optical behavior of MoS₂ simulates the photoconductivity of either the semiconductor or the metal, further indicating that the optical metal–insulator transition is coherent with its electrical counterpart. The electrical switchability of MoS₂ enables the development of an unprecedented and novel design optical sensor that can detect both visible and mid-IR (wavelength of 9.6 μm) ranges with a singular optoelectronic device.

中文翻译：

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二硫化钼的光学二元性：金属和半导体

可见光和红外光之间的两种不同的光-物质相互作用是不可切换的，因为迄今为止尚未阐明控制机制，这限制了光传感设备的有效光谱范围。_{在这项研究中，使用 MoS 2}的金属-绝缘体跃迁证明了有效光谱范围的调制。非简并MoS ₂在检测可见光时表现出光电导效应。相比之下，简并的 MoS ₂仅对中红外（不可见）光作出响应，通过自由载流子吸收显示光致加热效应。根据掺杂水平，MoS _{2的光学行为}模拟了半导体或金属的光电导率，进一步表明光学金属 - 绝缘体转变与其电对应物是相干的。_{MoS 2}的电可切换性使开发前所未有的新颖设计光学传感器成为可能，该传感器可以通过单个光电器件检测可见光和中红外（波长为 9.6 μm）范围。