High-Performance Room-Temperature UV-IR Photodetector Based on the InAs Nanosheet and Its Wavelength- and Intensity-Dependent Negative Photoconductivity

Low-dimensional narrow-band-gap III–V semiconductors have great potential in high-performance electronics, photonics, and quantum devices. However, high-performance nanoscale infrared photodetectors based on isolated two-dimensional (2D) III–V compound semiconductors are still rare. In this work, we demonstrate a new type of photodetector based on the InAs nanosheet. The photodetector has high optoelectronic response in the ultraviolet-infrared band (325–2100 nm) at room temperature. The high-performance photodetector has very high responsivity (∼1231 A/W), EQE (2.2 × 105 %), and detectivity (5.46 × 1010 Jones) to 700 nm light at low operating voltage (∼0.1 V). These results indicate that 2D InAs nanosheet devices have great potential in nano-optoelectronic devices and integrated optoelectronic devices. In addition, we observe for the first time that the InAs nanosheet devices have a negative photoconductivity (NPC) that is not only affected by the wavelength but also related to the optical power intensity of the light. After analyzing experimental data, we propose that the origin of the NPC may come from electron trapping, and two competing mechanisms of optical absorption and the photogating effect in the photoelectric response process cause the dependence on the light wavelength and optical power intensity.