Lateral MoS₂ p–n Junction Formed by Chemical Doping for Use in High-Performance Optoelectronics

TLDR

The study demonstrates a method to create a lateral homogeneous MoS₂ p‑n junction by partially stacking h‑BN as a mask to p‑dope MoS₂. The authors form the junction by partially stacking h‑BN layers as a hard mask to selectively p‑dope MoS₂. The fabricated junction exhibits a highly efficient photoresponse with an external quantum efficiency of ~7000 %, a specific detectivity of ~5 × 10¹⁰ Jones, a light‑switching ratio of ~10³, and ideal rectifying behavior, demonstrating low‑power operation and improved photodetection performance.

Abstract

This paper demonstrates a technique to form a lateral homogeneous 2D MoS2 p-n junction by partially stacking 2D h-BN as a mask to p-dope MoS2. The fabricated lateral MoS2 p-n junction with asymmetric electrodes of Pd and Cr/Au displayed a highly efficient photoresponse (maximum external quantum efficiency of ∼7000%, specific detectivity of ∼5 × 10(10) Jones, and light switching ratio of ∼10(3)) and ideal rectifying behavior. The enhanced photoresponse and generation of open-circuit voltage (VOC) and short-circuit current (ISC) were understood to originate from the formation of a p-n junction after chemical doping. Due to the high photoresponse at low VD and VG attributed to its built-in potential, our MoS2 p-n diode made progress toward the realization of low-power operating photodevices. Thus, this study suggests an effective way to form a lateral p-n junction by the h-BN hard masking technique and to improve the photoresponse of MoS2 by the chemical doping process.