Visualizing the Electronic Structure of Defects in Two-Dimensional Tungsten Disulfide

Recent experimental studies of van der Waals heterostructures have shown their great potential for novel device applications based on their exciting electronic, magnetic, and optical properties. For example, the semiconducting compounds in the transition metal dichalcogenide (TMD) family show promise to replace silicon as the semiconductor in electronic devices. These materials can be reliably synthesized via chemical vapor deposition (CVD) method on a large scale. CVD method also allows for defect engineering in 2D semiconductors. Incorporating defects in these materials has been shown to introduce new electronic properties that are not present in their pristine counterparts. In our work here, we use a solution-based CVD method to introduce metal substitution - V dopants- into a representative 2D semiconductor WS2. We use combined characterization techniques including conductive atomic force microscopy (CAFM), scanning transmission electron microscopy (STEM) and scanning tunneling microscopy (STM) to study the incorporated dopants. We highlight that the atomic-resolution CAFM characterizes local conductivity at individual dopant sites, enabling comprehensive studies of dopant properties combined with atomic structural and electronic structural information provided by TEM and STM, respectively.