Thermal Annealing Effects on Naturally Contacted Monolayer MoS₂

Abstract

Transition metal dichalcogenides such as MoS2, which can be produced in monolayer form, have attracted attention because of their interesting and potentially useful electrical and optical properties. These properties often depend sensitively on material properties such as defect density and crystallinity. Herein, the effects of postgrowth annealing on monolayer MoS2 grown using a novel chemical vapor deposition process are investigated. In this process bulk molybdenum patterns serve as the nucleation site and source material for high‐quality MoS2 material growth. After postgrowth thermal annealing, the photoluminescence is found to blueshift and become more uniform up to an annealing temperature of 300 °C. At higher temperatures, isolated monolayers begin to crack along the grain boundaries, which leads to variations in luminescence, whereas after annealing temperature of 200 °C, material anchored to the molybdenum patterns is found to easily ablate.

High Throughput Data-Driven Design of Laser-Crystallized 2D MoS2 Chemical Sensors: A Demonstration for NO2 Detection

“…Data-driven design of electronic sensors is an attractive approach to efficiently and rapidly correlate multibody intrinsic material properties relevant to sensor performance optimization . In the case of 2D MoS 2 chemical sensors, detection sensitivity is known to be non-monotonically responsive to the layer thickness, grain size, − and defect density. , Moreover, 2D sensor devices are often fabricated from a finite batch of samples grown by wafer-scale, relatively uniform techniques including thermal decomposition, metal–organic chemical vapor deposition, or magnetron sputtering. − Following the growth process, annealing strategies such as thermal or photonic annealing can tailor the crystallinity, induce defects, or even manipulate electronic properties. ,, For films produced by such wafer-scale techniques, the tuning of these material properties must be done on a per-sample basis or must rely on film variation intrinsically present . As a result, evaluating the relationships between the varying material properties is a time-consuming process.…”

“…27 Following the growth process, annealing strategies such as thermal or photonic annealing can tailor the crystallinity, induce defects, or even manipulate electronic properties. 17,30,31 For films produced by such wafer-scale techniques, the tuning of these material properties must be done on a per-sample basis or must rely on film variation intrinsically present. 32 As a result, evaluating the relationships between the varying material properties is a time-consuming process.…”