Probing the Intrinsic Optical Quality of CVD Grown MoS2

TL;DR

This study introduces a noninvasive photoluminescence spectroscopic method to evaluate the intrinsic optical and crystalline quality of CVD-grown MoS2, aiding in optimizing growth for optoelectronic applications.

Contribution

It proposes using the PL intensity ratio in air and vacuum as a new metric for intrinsic optical quality assessment of CVD MoS2.

Findings

PL intensity ratio correlates with optical quality

Low temperature PL reveals defect-related exciton emissions

Method enables noninvasive quality characterization

Abstract

The optical emission efficiency of two dimensional layered transition metal dichalcogenides (TMDs) is one of the most important parameter that affects their optoelectronic performance. Optimization of growth parameters of chemical vapor deposition (CVD) to achieve optoelectronics-grade quality TMDs is therefore highly desirable. Here, we present a systematic photoluminescence (PL) spectroscopic approach to assess the intrinsic optical and crystalline quality of CVD grown MoS2. We suggest that the intensity ratio between PL measured in air and vacuum could be used as an effective way to monitor the intrinsic optical quality of CVD MoS2. Low temperature PL measurements are also used to evaluate the structural defects in MoS2 by defect-associated bound exciton emission, which is well correlated with the field effect carrier mobilities of MoS2 grown at different temperatures. This work therefore provides a sensitive, noninvasive method to characterize the optical properties of TMDs, allow tuning of growth parameters for the development of optoelectronic devices.