Dresden 2006 – scientific programme
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O: Oberflächenphysik
O 49: Electronic structure IV
O 49.6: Talk
Friday, March 31, 2006, 12:30–12:45, WIL B321
Band structure of epitaxially grown CuInS2 films — •Carsten Lehmann1, Ralf Hunger2, and Christian Pettenkofer1 — 1Hahn-Meitner Institut, SE6, Berlin, Germany — 2TU Darmstadt, Oberflächenforschung, Inst. f. Materialforschung
The ternary compound semiconductor CuInS2 with a direct band gap of 1.53 eV seems to be very promising as absorber material for thin film solar cells. For a better understanding of the parameters determining the properties of a junction detailed information on the electronic structure is necessary. Besides a calculation of Zunger et al [1] no experimental data on the valence electronic structure of CuInS2 are available.
We report on thin epitaxial CuInS2 layers prepared on sulfur passivated GaAs (100). To have a better control on the deposition process we introduced a MOMBE type deposition with an organic sulfur precursor.
Clean and well defined surfaces were obtained despite a lattice mismatch of 2%. Samples were prepared in a dedicated UHV deposition and analysis system. Precharacterized samples were transferred by an UHV box within 15min to the TGM7 beamline at BESSY and investigated by ARUPS. We will discuss the obtained band structure with respect to available theoretical data and derive the effective mass from the valence band curvature. Implications of the observed reconstruction on the band structure will be discussed.
[1] E.J. Jaffe, A. Zunger, Phys. Rev. B 28, 1983, 5822