Room-Temperature Ultrabroadband Photodetection with MoS₂ by Electronic-Structure Engineering Strategy.

Abstract

Photodetection using semiconductors is critical for capture, identification, and processing of optical information. Nowadays, broadband photodetection is limited by the underdeveloped mid-IR photodetection at room temperature (RT), primarily as a result of the large dark currents unavoidably generated by the Fermi-Dirac distribution in narrow-bandgap semiconductors, which constrains the development of some modern technologies and systems. Here, an electronic-structure strategy is proposed for designing ultrabroadband covering mid- and even far-IR photodetection materials operating at RT and a layered MoS₂ is manifested with an engineered bandgap of 0.13 eV and modulated electronic state density. The sample is designed by introducing defect energy levels into layered MoS₂ and its RT photodetection is demonstrated for wavelengths from 445 nm to 9.5 µm with an electronic state density-dependent peak photoresponsivity of 21.8 mA W^-1 in the mid-IR region, the highest value among all known photodetectors. This material should be a promising candidate for modern optoelectronic devices and offers inspiration for the design of other optoelectronic materials.