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HL: Halbleiterphysik

HL 24: Photovoltaik I

HL 24.6: Vortrag

Dienstag, 9. März 2004, 19:00–19:15, H15

Admittance spectroscopy on single crystalline chalcopyrite thin films — •A. Dietz¹, J. Cieslak¹, J. Eberhardt¹, M. Gossla¹, Th. Hahn¹, H. Metzner¹, N. Rega², U. Reislöhner¹, S. Siebentritt², and W. Witthuhn¹ — ¹Friedrich-Schiller-Universität Jena, Institut für Festkörperphysik, Max-Wien-Platz 1, 07743 Jena — ²Hahn-Meitner-Institut, Glienicker Str. 100, 14109 Berlin

Thin films of the chalcopyrite semiconductors CuInS₂ (CIS), CuGaS₂ (CGS) and CuGaSe₂ (CGSe) were grown heteroepitaxially on Si- (CIS, CGS) and GaAs-substrates (CGSe), respectively. For the growth of the sulphur compounds, Molecular Beam Epitaxy (MBE) from elemental sources was utilized, while CGSe was deposited via metal organic vapour phase epitaxy (MOVPE).

After deposition, the samples were etched in KCN. Various metals including Al, Ti, Ni, Cr, Ag, and a Ga/In-eutectic were tested for their contact properties on the chalcopyrite epilayers. Schottky contacts were obtained by the evaporation of Al, while Ni gave reliable ohmic contacs. Thermal admittance spectroscopy (TAS) was performed on these samples to reveal their shallow doping. The TAS spectra show typically one large capacitance step representing a p-type dopant. The results are compared to those obtained for polycrystalline CGSe layers in solar cells.