ON THE CORRELATION BETWEEN THE SCANNING-TUNNELING-MICROSCOPY IMAGE IMPERFECTIONS AND POINT-DEFECTS OF LAYERED CHALCOGENIDES 2H-MX(2) (M=MO,W X=S, SE)

Numerous types of image imperfections are found in scanning tunneling microscopy (STM) images of layered transition-metal chalcogenides 2H-M X(2) (M=Mo, W; X=S, Se). In an effort to correlate between STM image i mperfections and point defects, we carried out a theoretical analysis of how point defects modify the energy spectrum of the ideal defect-fr ee MoS2 layer in the valence band and conduction band region and what types of image imperfections they lead to. We then surveyed representa tive STM image imperfections of the 2H-MX(2) compounds observed in our study and discussed what types of point defects they might be associa ted with. Our study shows that, to be able to infer the nature of poin t defects from observed STM image imperfections, it is essential to ca rry out controlled experiments from synthesis to STM measurements.