PHOTOELECTROCHEMICAL RESPONSE AND OPTICAL-ABSORPTION OF PYRITE (FES2) NATURAL SINGLE-CRYSTALS

Some properties of two different types of natural single crystals of pyrite (FeS2) have been investigated in order to understand their different photoelectrochemical responses: samples from Murgul (Turkey) show much higher photovoltages at all photon energies than samples from Logrono (Spain). Turkish crystals have higher resistivity, lower Hall mobility and lower carrier concentration than Spanish ones and, however, similar band gap energies, stoichiometric (S/Fe) ratios and Mossbauer spectra are shown by both types of pyrites. All these facts hint that the different photoresponse should be related to the concentration of impurities of both pyrites which have also been chemically analyzed. A very schematic analysis of the possible influence of the impurities is presented.