Multi‐Controllability of Ambipolar Photoconductivity in Transition Metal Dichalcogenides Van der Waals Heterostructures

Abstract

Abstract2D transition metal dichalcogenides (TMDs) and their van der Waals heterostructures possess great potential for optoelectronic applications thanks to their strong quantum confinement and flexibility in bandgap engineering. Photodetection based on TMDs utilizing photoconductance typically exhibits positive photoconductance resulting from the generation of photocarriers upon illumination. This study reports a SnSe2/MoS2 photodetector operating over a broadband range from deep ultraviolet to infrared wavelengths with not only a high responsivity and self‐powered feature but also ambipolar photoresponse with both positive and negative photoconductances to multi‐control parameters of wavelength, gate voltage, and laser power. The transition from positive to negative photoconductance by gate voltage and laser power indicates that charge recombination and interlayer exciton trapping result in negative photoconductance. The coexistence and controllable positive and negative photoconductance hold potential for multifunctional optoelectronic devices responding to multi‐control parameters.

Enhanced Electromechanical Response Due to Inhomogeneous Strain in Monolayer MoS2

“…In this work, we used PFM to examine electromechanical coupling in monolayer MoS 2 in the presence of highly inhomogeneous strain distributions via spontaneously formed nanobubbles, which frequently occur in 2D samples fabricated by common mechanical exfoliation techniques. − PFM measurements were carried out on mechanically exfoliated MoS 2 monolayers with a variety of nanobubble size and spatial distributions. In the following, small bubbles are defined as having diameters on the order of approximately 100 nm or less and large bubbles as having diameters of several hundred nanometers.…”