XAFS study on Al-doped ZnTe and ZnSe semiconductors powders

J.HOYA; J.I.LABORDE; L.C. DAMONTE

Encuentro; 24ª RAU; 2014

II-VI semiconductors are of interest due to their potential application as photovoltaic devices like hybrid solar cells. The efficiency of these devices may be improved mainly increasing charge carriers densities and interfacial processes. In order to reach this last purpose nanocrystalline materials are the best option as solar cells constituents. In this study we present zinc based semiconductors powders which optical and electrical properties have been modified by the Al presence acting as small quantities of dopant. The nanosized doped semiconductors (ZnSe and ZnTe) were obtained by mechanical milling which has been proved to be an effective and simple technique to produce nanocrystalline and large quantities of materials. Metal oxide Al2O3 together with ZnSe or ZnTe was milled in adequate proportion to obtain the desired concentration. Parameters such as initial concentrations, atmosphere and milling times were varied. X-ray Absorption Spectroscopy (XAFS) characterization on doped powders was done in order to probe cation sustitution. Undoped ZnSe and ZnTe nanocrystalline powders prepared in a similar way were analyze for comparison. The knowledge obtained can be of use to give direction to the improvement of the performance of hybrid organic/inorganic solar cells.