Growth of Oxide Compounds under Dynamic Atmosphere Composition

TL;DR

This paper discusses how to optimize atmosphere compositions during crystal growth to maintain desired oxidation states, using thermodynamic calculations to achieve self-adjusting oxygen partial pressures.

Contribution

It introduces a method based on equilibrium thermodynamics to determine dynamic atmosphere compositions for controlled crystal growth.

Findings

Thermodynamic calculations enable self-adjusting oxygen partial pressures.

Optimized atmospheres improve growth of ZnO, Ga2O3, and Fe{1-x}O crystals.

Method reduces impurities caused by residual gases.

Abstract

Commercially available gases contain residual impurities leading to a background oxygen partial pressure of typically several 10^{-6} bar, independent of temperature. This oxygen partial pressure is inappropriate for the growth of some single crystals where the desired oxidation state possesses a narrow stability field. Equilibrium thermodynamic calculations allow the determination of dynamic atmosphere compositions yielding such self adjusting and temperature dependent oxygen partial pressures, that crystals like ZnO, Ga2O3, or Fe{1-x}O can be grown from the melt.