Surface Defects Originated Photoresponse Study in Hbn-Res2 FETs

Electrical and optical transport properties of materials can be significantly affected by the imperfections in the crystal lattice. For instance, dislocations, defects, or grain boundaries. This paper presents a study on the electrical and optoelectrical properties of hBN-ReS 2 flakes field-effect transistors (FETs). The transistors demonstrate n-type behavior with an impressive electron mobility of 2.41 cm2/Vs. Additionally, the research highlights their remarkable photosensitive properties, exhibiting a photo-responsivity (Rλ) of 5.5 A/W and an external quantum efficiency (EQE) of 1240% when subjected to broad light irradiation at a wavelength (λ) of 550 nm. Under dark condition, there is a definite threshold voltage shift by 9.2 V between the device under vacuum and ambient air environment which is due to charge transfer takes place to the surface defects. Under light irradiation, photo-generated carriers (hole) get traps in those surface and bulk defects, which shows high photocurrent with 51.1% increment of I ds when compared to under air environment. There results here represent a crucial route in designing high performance two-dimensional optoelectronics device applications.