Nanoscale GaN Epilayer Grown by Atomic Layer Annealing and Epitaxy at Low Temperature

摘要： Heteroepitaxy with large thermal and lattice mismatch between the semiconductor and substrate is a critical issue for high-quality epitaxial growth. Typically, high growth temperatures (>1000 °C) are required to achieve high-quality GaN epilayers by conventional metal?organic chemical vapor deposition. In this study, the high-quality GaN heteroepitaxy is realized by atomic layer annealing and epitaxy (ALAE) at a low growth temperature of 300 °C. The layer-by-layer, in situ He/Ar plasma treatment at a low plasma power was introduced in each cycle of atomic layer deposition to contribute the e?ective annealing e?ect for signi?cant enhancement of the GaN crystal quality. The Penning e?ect is responsible for signi?cant improvement of the GaN crystal quality due to the incorporation of He into the Ar plasma. The high-resolution transmission electron microscopy, nano-beam electron di?raction, and atomic force microscopy reveal a high-quality nanoscale single-crystal GaN heteroepitaxy and a very smooth surface. The full width at half-maximum of the X-ray rocking curve of the GaN epilayer is as low as 168 arcsec. The low-temperature ALAE technique is highly bene?cial to grow high-quality nanoscale GaN epilayers for sustainable, energy-saving, and energy-e?cient devices including high-performance solid-state lighting, solar cells, and high-power electronics.