ZnO has a good lattice match and ideal structure for GaN epitaxy. ZnO thin films have been successfully used as buffer layers for GaN growth on both sapphire and SiC. The hexagonal crystal structure and crystallographic space group of ZnO, P63mc, is the same as that of GaN. The lattice constant is 3.2498 Å (in the a direction), resulting in a lattice mismatch of only 2.2% between ZnO and pure GaN and a perfect match between ZnO and InGaN alloys. There is little information on attempts to grow ZnO single crystals from a melt.

According to the literature and industry sources, the only two ways of making bulk single crystal ZnO are sublimation and hydrothermal techniques. The hydrothermal technique uses extremely reactive zinc-containing solutions, which requires platinum-lined hydrothermal vessels. Additionally, the crystal quality is poor, and the ultimate size is limited. The sublimation technique produces high quality material. However, the growth process is a slow process, which results in a costly product. As a result, the limited sources for single crystal ZnO price the material at approximately $5000 - 7500 per square inch