Photoelectrochemistry and Surface Studies of Copper Interaction with Rough Surfaces of p ‐ MoSe₂

Layered materials of the type , where X is a chalcogenide, have been widely used in photoelectrochemical cells. Their two‐dimensional structure makes these materials highly anisotropic in their electronic properties. The interaction of Cu²⁺ with the axial planes of have been studied by Auger electron spectroscopy as well as by photoelectrochemical methods. We present results on the photoelectrodeposition of Cu at rough surfaces of , i.e., surfaces having a high degree of axial planes exposed to the electrode/electrolyte interface. Cyclic voltammetry of Cu²⁺ at showed a quasireversible electron transfer process at ca. 350 mV vs. SCE. Photoelectrodeposition of Cu at rough surfaces of was performed at 170 and 0 mV vs. saturated calomel electrode while the semiconductor was under illumination. Auger electron spectroscopy depth profiles of the surface, after the photoelectrodeposition of Cu²⁺, indicates that at both potentials, and for long times of photoelectrodeposition, intercalation of Cu is occurring.