Atomic and electronic structures at ZnO and ZrO 2 interface for transparent thin-film transistors

Abstract

In this paper, we report the studies of atomic and electronic structures at ZnO and ZrO 2 interface. The epitaxial heterostructures were grown by laser molecular beam epitaxy and the interface atomic structure was determined by using highresolution transmission electron microscopy (TEM). Band alignment for high-k ZrO 2 layer on ZnO was investigated by in situ X-ray photoemission spectroscopy (XPS) characterization and first-principles calculations based on density functional theory (DFT). The valence and conduction band offsets (CBOs) were found to be 0.27±0.05 eV and 2.16±0.05 eV, respectively. The results are in good agreement with values from theoretical calculations. The large CBO and small lattice mismatch between ZnO and ZrO 2 suggest potential for ZrO 2 to be used as a gate dielectric in ZnO-based transparent electronic devices. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.