Hybrid InSe Nanosheets and MoS2 Quantum Dots for High-Performance Broadband Photodetectors and Photovoltaic Cells

Abstract

To find new materials to substitute for conventional silicon (Si)-based technology that has been extensively used in logic circuits for decades, researchers have explored a wide plethora of materials to overcome the scaling limit of Si-based devices. Hybrid structures-based phototransistors are intensively studied recently to achieve high-performance optoelectronic devices. The hybridization of 2D materials and quantum dots (QDs) is one of the ideal platforms for photodetection applications with the merits of high detection sensitivity and wide wavelength coverage. The broadband absorption of a hybrid device stems from various absorbers with multiple bandgaps to create high photocurrent from an efficient exciton generation mechanism under illumination. Here, a new optoelectronic hybrid device of an indium selenide (InSe) nanosheets-based phototransistor is introduced decorated with molybdenum disulfide (MoS2) QDs to possess the photoresponsivity (Rλ) of 9304 A W−1, which is ≈103 times higher than Rλ ≈ 12.3 A W−1 of the previously reported InSe photodetector. The escalated Rλ of this hybrid photodetector is due to the additional injection of photoexcited charge carriers from MoS2 QDs to the InSe phototransistor. Finally, the photovoltaic performance of this MoS2/InSe hybrid device is investigated. The open-circuit voltage (Voc) and short-circuit current density (Jsc) are determined to be 0.52 V and 15.6 mA cm−2, respectively, rendering the photovoltaic efficiency of 3.03%. The development of this MoS2/InSe hybrid phototransistor with high device performance and wide wavelength photodetection will bring a new type of optoelectronic applications in the future. Nanosheets