Kinetic model of II-VI(001) semiconductor surfaces: Growth rates in atomic layer epitaxy

TL;DR

This paper develops a kinetic lattice gas model for II-VI(001) semiconductor surfaces to simulate atomic layer epitaxy growth rates, revealing temperature-dependent regimes and aligning qualitatively with experimental data.

Contribution

It introduces a novel lattice gas model incorporating anisotropic interactions and Te-dimerization to study ALE growth dynamics of II-VI semiconductors.

Findings

At high temperature, growth rate is limited to 0.5 layers per cycle.

At low temperature, complete layers of CdTe are added each cycle.

The model's temperature dependence aligns qualitatively with experimental observations.

Abstract

We present a zinc-blende lattice gas model of II-VI(001) surfaces, which is investigated by means of Kinetic Monte Carlo (KMC) simulations. Anisotropic effective interactions between surface metal atoms allow for the description of, e.g., the sublimation of CdTe(001), including the reconstruction of Cd-terminated surfaces and its dependence on the substrate temperature T. Our model also includes Te-dimerization and the potential presence of excess Te in a reservoir of weakly bound atoms at the surface. We study the self-regulation of atomic layer epitaxy (ALE) and demonstrate how the interplay of the reservoir occupation with the surface kinetics results in two different regimes: at high T the growth rate is limited to 0.5 layers per ALE cycle, whereas at low enough T each cycle adds a complete layer of CdTe. The transition between the two regimes occurs at a characteristic temperature and its dependence on external parameters is studied. Comparing the temperature dependence of the ALE growth rate in our model with experimental results for CdTe we find qualitative agreement.