Atomic scale defects in semiconductors enable their technological applications and realization of novel quantum states. Using scanning tunneling microscopy and spectroscopy complemented by ab-initio calculations we determine the nature of defects in the anisotropic van der Waals layered semiconductor ReS2. We demonstrate the in-plane anisotropy of the lattice by directly visualizing chains of rhenium atoms forming diamond-shaped clusters. Using scanning tunneling spectroscopy we measure the semiconducting gap in the density of states. We reveal the presence of lattice defects and by comparison of their topographic and spectroscopic signatures with ab initio calculations we determine their origin as oxygen atoms absorbed at lattice point defect sites. These results provide an atomic-scale view into the semiconducting transition metal dichalcogenides, paving the way toward understanding and engineering their properties.
@article{arxiv.2010.04695,
title = {Prevalence of oxygen defects in an in-plane anisotropic transition metal dichalcogenide},
author = {Ryan Plumadore and Mehmet Baskurt and Justin Boddison-Chouinard and Gregory Lopinski and Mohsen Modaresi and Pawel Potasz and Pawel Hawrylak and Hasan Sahin and Francois M. Peeters and Adina Luican-Mayer},
journal= {arXiv preprint arXiv:2010.04695},
year = {2020}
}