Chemical Vapor Deposition Growth of Vertical MoS₂ Nanosheets on p-GaN Nanorods for Photodetector Application

Abstract

Vertically oriented multilayered MoS2 nanosheets were successfully grown on p-GaN nanorod substrate using chemical vapor deposition (CVD) method. The p-GaN nanorod substrate was fabricated by dry etching employing self-assembled nickel (Ni) nanopartical as mask. Photoluminescence (PL) and Raman characterizations demonstrate the multilayered structure of MoS2 nanosheet growth on p-GaN nanorods as compared with the referential monolayer MoS2 on GaN wafer substrate under the same growth procedure. The growth model of vertical MoS2 nanosheet formed on GaN nanorods is evidently proposed according to the first-principle calculations. More importantly, it is demonstrated here that the as-grown vertical MoS2 nanosheets/p-GaN nanorod heterostructure holds promising applications in photodetector device, where high optical gain and broad spectral response in the visible range have been obtained.

Band Alignment Engineering in Two‐Dimensional Transition Metal Dichalcogenide‐Based Heterostructures for Photodetectors

“…The fourth type of the energy band structure is constructed by TMDs and wide‐bandgap materials, such as ZnS, ZnO, β ‐Ga 2 O 3 , GaN, TiO 2, and so on, all of which have a wide bandgap greater than 3.1 eV. [ 161–164 ] Here we will first discuss the carrier transportation mechanism of these types of heterostructure photodetectors using MoS 2 –ZnS as a typical example. As discussed, MoS 2 and ZnS show n‐type characteristics but the electronic affinity of ZnS is smaller than MoS 2 , and thus ZnS has a higher Fermi level than MoS 2 .…”

AlGaN‐based p‐i‐p‐i‐n solar‐blind ultraviolet avalanche photodetectors with modulated polarization electric field

“…Ultraviolet (UV) photodetectors have been extensively investigated due to their great applications in missile detection and interception, flame and environment monitoring, chemical and biological sensing, UV astronomy and spectroscopy. [1][2][3][4] Compared with the conventional costly, bulky and fragile Si-based photomultiplier tubes (PMTs), and AlGaNbased avalanche photodetectors (APDs) express greatly suitable candidates for PMTs due to their high sensitivity and reliability in UV detection. 5,6 Moreover, AlGaN compounds also have the intrinsic the solar blindness, which can extend their applications to solar-blind UV detections and reduce optical filter requirement for the elimination of natural background radiation.…”

“…Ultraviolet (UV) photodetectors have been extensively investigated due to their great applications in missile detection and interception, flame and environment monitoring, chemical and biological sensing, UV astronomy and spectroscopy 1‐4 . Compared with the conventional costly, bulky and fragile Si‐based photomultiplier tubes (PMTs), and AlGaN‐based avalanche photodetectors (APDs) express greatly suitable candidates for PMTs due to their high sensitivity and reliability in UV detection 5,6 .…”

One-step synthesized PbSe nanocrystal inks decorated 2D MoS2 heterostructure for high stability photodetectors with photoresponse extending to near-infrared region

“…Two-dimensional layered transition metal dichalcogenides (TMDs) with the formula of MX 2 (M = Mo, W; X = S, Se) have been widely employed as functional materials for promising electronics and optoelectronic devices in recent years due to their unique physical and outstanding electronic properties, 1,2 including high carrier mobility, 3 dimensional-dependent properties, 4 easy integration with flexible devices, 5 etc. Among the TMD family, molybdenum disulfide (MoS 2 ) is a typical semiconductor with a layered-dependent bandgap characteristic, 6 exhibiting a direct band gap of 1.8 eV for monolayer MoS 2 while an indirect band gap of 1.3 eV for multilayered MoS 2 .…”