Hot-electron luminescence in aged electrodeposited CdSe liquid-junction solar cell

Abstract

We have utilized Raman spectroscopy and scanning Auger electron spectroscopy (AES) to probe the surface of polycrystalline, electrodeposited CdSe photoelectrodes which have been aged in a polysulfide electrolyte under illumination and in darkness. We have observed characteristic ‘‘hot-electron’’ luminescence at multiples of ωLO (CdS)=305 cm−1 in the light-aged electrode, indicating that a surface layer of CdS has been formed. AES profiling shows that extensive substitution of S for Se has occurred, in the light-aged electrode alone, to a depth of ∼600 Å. Measurements at 300 K suggest that Raman scattering can be a useful, in situ, contactless, nondestructive probe of CdS formation.