Dresden 2011 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 44: Poster Session I

HL 44.86: Poster

Dienstag, 15. März 2011, 18:00–21:00, P3

Determination of the band offset for the heterostructure ZnO/Cu₂O and ZnS/Cu₂O via X-Ray Photoelectron Spektroscopy (XPS) — •Benedikt Kramm, Andreas Laufer, Achim Kronenberger, Swen Graubner, Daniel Reppin, Alba Seibert, Philipp Schurig, Angelika Polity, and Bruno K. Meyer — 1. Physikalisches Institut, Justus-Liebig-Universität, Heinrich-Buff-Ring 16, 35392 Gießen, Germany

ZnO and Cu₂O are direct band-gap semiconductors. Both are promising materials for electronic devices like diodes, transistors or solar cells. Important is, that ZnO and Cu₂O contain only non toxic und sustainable elements. Due to a band-gap energy of 2.1 eV for Cu₂O a high absorption in the visible light spectrum could be obtained which is suitable for solar cells. We produced a heterojunction of intrinsic p-type Cu₂O and hydrogen doped n-type ZnO or ZnS on sapphire using sputter deposition. Investigating the energy band structure of the thin film heterojunction ZnO/Cu₂O via XPS yield to be a type II alignment with a valence-band offset between 2.4 − 2.7 eV. Furthermore the band offset between ZnS and Cu₂O, using ZnS as a buffer-layer for the heterostructure ZnO/ZnS/Cu₂O, was explored. For the band offset structure of the whole system the band offset values for ZnS/ZnO, determined by Persson [1], have been used.

[1] Perrson et al. Strong Valance-Band Offset Bowing of ZnO_1−xS_x Enhances p-Type Nitrogen Doping of ZnO-like Alloys, Phys. Rev. Lett., Okt 2006, 97(14):146403