Dresden 2009 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 18: Impurities/amorphous semiconductors
HL 18.2: Talk
Tuesday, March 24, 2009, 12:15–12:30, POT 151
First-principles calculations on self-diffusion in indium oxide — •Péter Ágoston1, Paul Erhart2, Andreas Klein1, and Karsten Albe1 — 1Technische Universität Darmstadt, Institut für Materialwissenschaft, Petersenstr. 23 64287 Darmstadt — 2Lawrence Livermore National Lab, California, USA
Indium oxide/ITO (indium tin oxide) is one of the most commonly used TCO materials (transparent conducting oxide). Although it is well known that point defects govern the materials’ functional properties, so far very little is known about their thermodynamic and kinetic properties. Defect concentrations sensitively depend on temperature, oxygen processing gas composition (oxygen partial pressure) and impurity level like the commonly used tin substitutional doping. Thus, different deposition techniques and temperature processing steps directly affect the defect equilibria and consequently the materials properties, which makes a more detailed understanding highly desirable. Therefore, we have conducted extensive calculations based on density functional theory in order to calculate the formation and migration energies of the dominant intrinsic point defects. Additionally, we have derived the entropy contributions to defect formation and migration in a rigorous way. Using this input data we are able to calculate the Fermi energy in the material as a function of temperature, oxygen partial pressure and doping. The defect concentrations at the calculated Fermi energy are then used to predict the diffusivity at different environmental conditions.