Epitaxial Growth and Transport Properties of High-Mobility ZnO-Based Heterostructures

Optimization of growth conditions is most important for extracting desired material properties, but it always requires time-consuming experiments. The temperature gradient method was applied for high-throughput optimization of the growth temperature by pulsed laser deposition to ZnO-based heterostructures. Surface morphology, photoluminescence, and electrical transport properties depend systematically on the growth temperature. Consequently, enhancement of two-dimensional growth, as detected from atomic force microscope images, can elucidate good physical properties, e.g., the observation of higher-order exciton emissions and highest electron mobility. By further optimizing the structure of heterojunction, we found growth conditions enabling the quantum Hall effect at the ZnO/MgxZn1-xO heterointerface.