Modulating the Photoresponse Performance of Two‐Dimensional GeSe Photodetectors in Visible Region by Ion Irradiation

Abstract

Abstract The 2D GeSe‐based photodetectors have exhibited ultrahigh photoresponsivity (Rλ), sensitive‐specific detectivity (D*), and large external quantum efficiency (EQE) in previous researches. Ion beam techniques have been utilized to effectively modify the surface of nanomaterials for recent years. Herein, the authors propose to engineer the 2D GeSe nanosheets via low‐energy ion irradiation for improving the photoresponse in visible region. The nonmetallic nitrogen and metallic silver elements are selected to modulate the performance of 2D GeSe FETs, respectively. The results show that N‐irradiated GeSe nanosheets have exhibited twice faster photoresponse for 532 nm laser for making up the trailing phenomenon in the decay process during the dynamic response of pristine 2D GeSe. More importantly, via Ag ion irradiation, a self‐driven and higher photoresponsivity GeSe‐based photodetector is realized. The Ag‐irradiated GeSe nanosheets have shown the considerably high Rλ of 9.6 × 102 A W−1 with no bias and no gate voltage applied. The work provides a new direction for modification of other 2D materials by ion beam technique for optoelectronic devices.

Keywords

• GeSe nanosheets
• low‐energy ion irradiation
• photodetectors
• photo‐generated carriers
• photoresponse modulation