Modeling the Transport and Reaction Mechanisms of Copper Oxide CVD

In this paper we consider the CVD of copper oxide, a semiconductor with demonstrated potential for solar hydrogen production by the photo-electrochemical (PEC) splitting of water. Extensive experiments with a hot-wall CVD reactor and a cuprous iodide/oxygen precursor system are conducted, revealing unexpected film deposition patterns and temperature/oxygen partial pressure dependencies. An evolutionary sequence of mathematical models is developed to understand the observed behavior, starting with an empirical response surface model (RSM) to rigorously determine the trends indicated in the data. Then, a series of physics-based models are developed to gain a theoretical understanding of the thermodynamic, reaction, and chemical species transport mechanisms at work in this reactor. In contrast to previously published research where gas-phase reaction and particle nucleation were identified as the key processes, our model predictions suggest the deposition process is largely governed by surface reactions.