Advances in atomistic modeling for epitaxial growth of nitride semiconductors: a DFT-based approach

The growth of high-quality epitaxial thin films of nitride semiconductors is essential for the development of energy-efficient power electronic devices as well as advanced optoelectronic applications. To enhance the performance of these materials, strict control over crystal growth conditions and a comprehensive understanding of surface structures and growth kinetics are indispensable. However, the mechanisms that govern epitaxial crystal growth remain incompletely understood due to the inherent complexity of surface structures and the dynamic nature of the growth processes. In this context, computational materials science, encompassing not only microscopic approaches such as density functional theory (DFT) and molecular dynamics but also mesoscale techniques like phase-field modeling, has emerged as an increasingly valuable tool adopted by both theorists and experimentalists for interpreting experimental results and predicting material properties. This highlight presents recent advances in computational studies of epitaxial crystal growth in nitride semiconductors, with a particular focus on state-of-the-art methods based on DFT. The techniques employed to investigate surface reconstructions and growth kinetics during epitaxial growth are introduced. Several case studies are discussed that reveal realistic surface reconstructions of nitride semiconductor surfaces such as GaN(0001) and AlN(0001). In addition, the growth processes involving adsorption, desorption, and migration behaviors of adatoms are examined. A key aspect of understanding epitaxial growth mechanisms is the presence of steps and kinks on the surface, which are inevitably formed during the growth process. Recent studies demonstrate that quantum-theory-based simulations provide a microscopic understanding of the complex phenomena associated with epitaxial crystal growth.