Regensburg 2004 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 12: Poster I

HL 12.7: Poster

Montag, 8. März 2004, 16:30–19:00, Poster A

Intrinsic Defect Levels in Epitaxial CuGaS₂ on Si(111) — •J. Eberhardt¹, J. Cieslak¹, R. Goldhahn², Th. Hahn¹, H. Metzner¹, U. Reislöhner¹, and W. Witthuhn¹ — ¹Friedrich-Schiller-Universität Jena, Institut für Festkörperphysik, Max-Wien-Platz 1, 07743 Jena — ²Institut für Physik, TU Ilmenau, PF 100565, 98684 Ilmenau

The chalcopyrite semiconductor CuGaS₂ (CGS) with its direct band gap of E_gap=2.5eV (T=5K) is a promising wide-band gap material for photovoltaic applications such as tandem solar cells. However, the performance of these devices depends cruically on the intrisic defects in CGS responsible for its electrooptical properties.

In this work, photoluminesence (PL) measurements were performed on thin CGS films which were grown epitaxially on Si(111) by means of Molecular Beam Deposition (MBE).

Excitonic emissions were observed throughout the whole covered temperature range from 5 to 300 K. Additionally emissions related to shallow defect levels were detected between 2.35 and 2.45eV at low temperatures. Based on the identification of two free-to-bound and the two related donor-acceptor transitions, a model for intrinsic defect levels in CGS including one shallow donor and two acceptor states is proposed.