Density Functional Theory Study of the Gas Phase and Surface Reaction Kinetics for the MOVPE Growth of GaAs 1- y Bi y

The kinetics of chemical reactions occurring during the metal-organic vapor phase epitaxy (MOVPE) of GaAs Bi have been studied using density functional theory (DFT). GaAs Bi is a metastable semiconductor alloy that has potential applications in high-performance long-wavelength emitters. Its growth is complicated by the low solubility of Bi within the GaAs lattice, which leads to phase segregation under conventional III-V semiconductor growth conditions. In this study, the thermochemical and kinetic parameters of the gas-phase pyrolysis and surface reactions occurring in the MOVPE growth of GaAs Bi from trimethyl bismuth, tertiary butyl arsine, and triethyl gallium are calculated from first-principles electronic structure and vibrational mode calculations. These calculations indicate that the pyrolysis products AsH and Bi(CH ) are the principle sources for the deposition of their respective metallic elements. The surface-adsorbed methyl species and their interaction with the gas-phase pyrolysis products lead to the self-limiting growth described within this model. The calculated thermochemical and kinetic values provide initial parameters for the development of a microkinetic model of GaAs Bi deposition.