Understanding nonpolar GaN growth through kinetic Wulff plots

In this paper we provide explanations to the complex growth phenomena of GaN heteroepitaxy on nonpolar orientations using the concept of kinetic Wulff plots (or upsilon-plots). Quantitative mapping of kinetic Wulff plots in polar, semipolar, and nonpolar angles are achieved using a differential measurement technique from selective area growth. An accurate knowledge of the topography of kinetic Wulff plots serves as an important stepping stone toward model-based control of nonpolar GaN growth. Examples are illustrated to correlate growth dynamics based on the kinetic Wulff plots with commonly observed features, including anisotropic nucleation islands, highly striated surfaces, and pentagonal or triangular pits. (C) 2008 American Institute of Physics. [DOI: 10.1063/1.3009969]