DIGITAL IMAGING OF THE EFFECT OF PHOTOETCHING ON THE PHOTORESPONSE OFN-TYPE TUNGSTEN DISELENIDE AND MOLYBDENUM DISELENIDE SINGLE-CRYSTAL ELECTRODES

The effect of photoetching on the photoelectrochemical behavior of n-M oSe2 and n-WSe2 layered compounds in contact with iodide electrolytes has been studied by the scanning microscope for semiconductor characte rization (SMSC), a technique for imaging physical effects photoinduced at the semiconductor-electrolyte interface. Photocurrent images in co mbination with localized intensity modulated photocurrent spectroscopy (IMPS) measurements performed with the SMSC, on a micrometric scale, show that the increase of photoresponse observed after photoetching is due to the generation at the van der Waals surface of defects able to hinder surface recombination and to promote interfacial charge transf er through the covalent interaction with photogenerated triiodide ions .