Wavelength‐Controlled Photocurrent Polarity Switching in BP‐MoS2 Heterostructure. (20th March 2022)

• Record Type: Journal Article
• Authors: Jawa, Himani; Varghese, Abin; Ghosh, Sayantan; Sahoo, Srilagna; Yin, Yuefeng; Medhekar, Nikhil V; Lodha, Saurabh
• Is Part Of: Advanced functional materials. Volume 32:Number 25(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-03-20
• Subjects: 2D materials -- black phosphorus -- MoS 2 -- negative persistent photoconductance -- negative photoconductance -- recombination -- van der Waals heterostructure; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.202112696
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: Layered 2D van der Waals semiconductors and their heterostructures have been shown to exhibit positive photoconductance (PPC) in many studies. A few recent reports have demonstrated negative photoconductance (NPC) as well that can enable broadband photodetection besides multi‐level optoelectronic logic and memory. Controllable and reversible switching between PPC and NPC is a key requirement for these applications. This report demonstrates visible‐to‐near infrared wavelength‐driven NPC and PPC, along with reversible switching between the two, in an air stable, high mobility, broadband black phosphorus field effect transistor covered with a few layer MoS2 flake. The crossover switching wavelength can be tuned by varying the MoS2 bandgap through its flake thickness and the NPC and PPC photoresponsivities can be modulated using electrostatic gating as well as laser power. Recombination‐driven NPC and PPC, as supported by density functional theory calculations, allows for reversible switching. Further, gate voltage‐dependent negative persistent photoconductance is well‐suited for optosynaptic applications. Abstract : Controllable and reversible photoconductance polarity switching can enhance broadband photodetection performance besides enabling multi‐level optoelectronic logic and memory applications. In this article, wavelength‐controlled negative (NPC) and positive photoconductance (PPC), along with reversible switching between the two, have been demonstrated in a BP‐MoS2 heterostructure phototransistor. The NPC‐to‐PPC crossover wavelength can be tuned by varying MoS2 thickness.