THE SCANNING MICROSCOPE FOR SEMICONDUCTOR CHARACTERIZATION (SMSC) - COMPARATIVE-STUDY OF THE INFLUENCE OF SURFACE-DEFECTS ON THE PHOTOELECTROCHEMICAL BEHAVIOR OF N-WSE2 AND N-MOSE2 LAYERED COMPOUNDS

The role of surface defects on the modulated photocurrent response of the layered semiconducting compounds n-WSe2 and n-MoSe2 has been studi ed with the help of the scanning microscope for semiconductor characte rization (SMSC). Global and localized measurements of the flatband pot ential V-fb have been carried out by applying the electrolyte electror eflectance method. The photocurrent images obtained at a potential clo se to V-fb show a significant contrast between smooth and corrugated z ones. In the light of localized SMSC measurements, these results provi de information about the influence of surface inhomogeneities on the s emiconductor photoresponse, The enhanced interaction of I-3(-) electro lyte species with surface defects produces an improvement in photoresp onse for both semiconductors. The influence of surface roughness on th e position of the excitonic signal A of the tungsten semiconductor see ms to indicate important differences in the anisotropic behavior of bo th layered compounds.