Band alignments were measured by x-ray photoelectron spectroscopy for thin films of ZnO on polycrystalline Sn:In2O3 (ITO) and single crystal CdTe. Hybrid density functional theory calculations of epitaxial zinc blende ZnO(001) on CdTe(001) were performed to compare with experiment. A conduction band offset of -0.6 eV was measured for ZnO/ITO, which is larger than desired for efficient electron injection. For ZnO/CdTe, the experimental conduction band offset of 0.25 eV is smaller than the calculated value of 0.67 eV, likely due to the TeOx layer at the ZnO/CdTe interface. The measured conduction band offset for ZnO/CdTe is favorable for photovoltaic devices.
Revised: August 18, 2014 |
Published: December 28, 2011
Citation
Kaspar T.C., T.C. Droubay, and J.E. Jaffe. 2011.ZnO/Sn:In2O3 and ZnO/CdTe band offsets for extremely thin absorber photovoltaics.Applied Physics Letters 99, no. 26:263504.PNNL-SA-83072.doi:10.1063/1.3672218