GaN epitaxy on thermally treated c-plane bulk ZnO substrates with O and Zn faces

Abstract

ZnO is considered as a promising substrate for GaN epitaxy because of stacking match and close lattice match to GaN. Traditionally, however, it suffered from poor surface preparation which hampered epitaxial growth in general and GaN in particular. In this work, ZnO substrates with atomically flat and terrace-like features were attained by annealing at high temperature in air. GaN epitaxial layers on such thermally treated basal plane ZnO with Zn and O polarity have been grown by molecular beam epitaxy, and two-dimensional growth mode was achieved as indicated by reflection high-energy electron diffraction. We observed well-resolved ZnO and GaN peaks in the high-resolution x-ray diffraction scans, with no Ga 2 ZnO 4 phase detectable. Low-temperature photoluminescence results indicate that high-quality GaN can be achieved on both O-and Zn-face ZnO.

New approaches for calculating absolute surface energies of wurtzite (0001)/(0001¯): A study of ZnO and GaN

“…Therefore, it's very challenging to grow high quality GaN thin films on ZnO substrates, however, high quality ZnO thin film on GaN substrate is possible [53][54][55][56][57][58][59][60][61][62][63][64][65]. Indeed, 3D-like growth of GaN on ZnO substrate has already been observed [58,60].…”

Effect of annealing atmosphere on the quality of ZnO crystal surface

“…The way to improve morphological quality of the ZnO substrate after chemo-mechanical polishing is thermal annealing in the air [1,2]. Even the annealing of ZnO single crystal in the air at relatively low (up to 800 °C) temperature can improve the surface structure on the O-terminated (000 1) surface [3] and the 8° off-axis oriented surface of the crystal [4].…”

Flux Bridgman growth and the influence of annealing temperatures on PL properties of ZnO single crystals

“…It has been recognized as a promising candidate for ultraviolet laser source and ultraviolet detectors [2,3]. The same crystal structure and close lattice parameters to that of GaN make it the ideal substrate for epitaxial growth of high-quality GaN films [4]. ZnO crystal is also expected to be a diluted magnetic semiconductor (DMS) above room temperature when doped with 3d transition metal (TM) atoms.…”