Semiconductor–Insulator–Semiconductor Diode Consisting of Monolayer MoS₂, h-BN, and GaN Heterostructure

TLDR

The authors propose a semiconductor‑insulator‑semiconductor diode comprising monolayer MoS₂, h‑BN, and p‑GaN for high‑performance nanoscale optoelectronics. They grow 1‑L MoS₂ and h‑BN by CVD, vertically stack them on p‑GaN via wet transfer, verify the stack with PL and Raman, and evaluate device performance through I‑V and photocurrent measurements. Both the SIS and conventional p‑n diodes exhibit rectifying behavior, but the SIS device shows higher current and threshold voltage, indicating tunneling as the dominant transport mechanism.

Abstract

We propose a semiconductor-insulator-semiconductor (SIS) heterojunction diode consisting of monolayer (1-L) MoS2, hexagonal boron nitride (h-BN), and epitaxial p-GaN that can be applied to high-performance nanoscale optoelectronics. The layered materials of 1-L MoS2 and h-BN, grown by chemical vapor deposition, were vertically stacked by a wet-transfer method on a p-GaN layer. The final structure was verified by confocal photoluminescence and Raman spectroscopy. Current-voltage (I-V) measurements were conducted to compare the device performance with that of a more classical p-n structure. In both structures (the p-n and SIS heterojunction diode), clear current-rectifying characteristics were observed. In particular, a current and threshold voltage were obtained for the SIS structure that was higher compared to that of the p-n structure. This indicated that tunneling is the predominant carrier transport mechanism. In addition, the photoresponse of the SIS structure induced by the illumination of visible light was observed by photocurrent measurements.