Dresden 2011 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 85: Poster Session II

HL 85.65: Poster

Thursday, March 17, 2011, 18:00–21:00, P4

A theoretical investigation on the Cd doping of CuIn₅Se₈ — •Janos Kiss, Thomas Gruhn, and Claudia Felser — Institut für Anorganische Chemie und Analytische Chemie, Johannes Gutenberg-Universität, D-55099 Mainz, Germany

Due to its attractive optical, electrical, and chemical properties the ternary CuInSe₂ (CIS) chalcopyrite-type semiconductor is widely employed as absorber layer in thin film photovoltaic devices. In the industrial fabrication of thin film solar cells on top of the CIS layer a CdS films is deposited as buffer layer. Despite the exhaustive experimental and theoretical research, the atomic and electronic structure of the CIS–CdS interface is not well understood due to its complex nature. In the contemporary literature it is well accepted that the CIS surface regions are Cu-depleted and doped with Cd through the diffusion of Cd atoms from the buffer layer. Still, the concentration of the Cd dopant atoms and their arrangement in the Cu-depleted CIS is not yet unambiguously determined. To gain new insights on the doping of Cu-depleted CIS phases, we have investigated the Cd doping of bulk CuIn₅Se₈ via performing density functional theory (DFT) calculations on large supercells. We found that bulk CuIn₅Se₈ can be doped with Cd up to a Cd concentration of about 0.6–0.8%. Moreover, our calculations show that energetically it is favorable for Cd dopant atoms to occupy Cu antisites in CuIn₅Se₈.