Suspended ReSi FET for improved photocurrent-time response

Abstract

Strong light-matter interaction in 2D transition metal dichalcogenides (TMDs) presents a significant opportunity for many optoelectronic applications [1-7]. In photodetector devices, the transit time of photogenerated carriers is limited by their mobility, which affects the photoconductive gain and response time of the device. In this work, we report significant improvement in photocurrent-time response of few layer suspended ReS2-based FETs under broad laser beam illumination. High carrier life time in ReS2 results from the presence of traps [1, 2]. Suspended ReS2 devices have less interface defects [5] as compared to supported (on SiO2) transistors, which helps reduce the life time of the photogenerated carriers [1] and hence improve the photocurrent-time response of the device. Further, improved mobility in the suspended devices due to fewer interface traps also helps to enhance the photocurrent-time response.