Berlin 2015 – scientific program
DS 36.106: Poster
Thursday, March 19, 2015, 09:30–12:00, Poster A
Spectroscopic investigation of the electronic structure of HfO2 thin films — •Silma Alberton Corrêa, Simone Brizzi, Massimo Tallarida, and Dieter Schmeißer — Department of Applied Physics and Sensors, Brandenburg University of Technology, 03046 Cottbus, Germany
HfO2 is of current interest as a material for memristive and ferroelectric devices. In this work, we used spectroscopic techniques to evaluate the electronic structure and defects mechanisms in thin HfO2 films deposited by atomic layer deposition and by metal-organic chemical vapour deposition. The partial density of states for the valence and the conduction bands was determined by the detailed analysis of the O1s resonance profile by resonant photoelectron spectroscopy. From the relative contributions we find a CNL 6.5 eV referred to Evac. We also find that the positions of valence band maximum and conduction band minimum, the excitation range for the polaronic states and the range of charge transfer band were not influenced by the preparation conditions. All films exhibit a band gap of 6.2 eV. However, the Fermi level position was found to vary within about 1.2 eV depending on the preparation conditions, which we argue that is due to the presence of charges within the films. This explains why the position of the Fermi level depends on the individual preparation parameters.