Tip-Enhanced Raman Spectroscopy Studies of Defects in Few-Layer MoS­_2­

Tip-enhanced Raman spectroscopy (TERS) has become a powerful technique for studying chemical information at the nanoscale [1,2]. In recent years, it has been applied extensively to study a variety of  two-dimensional semiconductors [3,4]  as these materials have seen increased use in electronic and optoelectronic devices. Since the device performance can be heavily influenced by defects and other types of inhomogeneities in these materials [5-7], it becomes vital to probe these local variations and understand their correlation with device performance. Here, we employ TERS to investigate nanoscale bubbles and wrinkles formed in mechanically exfoliated molybdenum disulfide (MoS₂) thin films. By identifying characteristic features in the TERS spectra, we aim to investigate the correlation between strain and vibrational modes and try to reveal how different types of defects alter the chemical bonding structures.