Wu, Songhao; Ma, Chicheng; Yang, Han; Liu, Zichun; Ma, Yuanxiao; Yao, Ran; Zhang, Yiyun; Yang, Hua; Yi, Xiaoyan; Wang, Junxi; Wang, Yeliang Source: CrystEngComm, 2024;

Abstract:

High-quality β-(AlxGa1−x)2O3 thin films are fabricated through face-to-face annealing on sapphire substrates covered with epitaxial Ga2O3. Al atoms during high-temperature annealing are uniformly diffused from the sapphire substrate into the overlying Ga2O3 for (AlxGa1−x)2O3 formation. The transformation of the (−201) crystal facet into the (300) crystal facet is observed, which is likely due to the lowest Esurf of the (100) surface. The crystallinity can be further improved with increasing the annealing temperatures and the duration of the thermal treatment under a tolerance limit of 1400 °C, which also increases the Al content to 0.68 in β-(AlxGa1−x)2O3 with a bandgap of up to 6.0 eV. As a result, highly-crystalline (300)-plane β-(AlxGa1−x)2O3 is obtained with a low X-ray diffraction (XRD) full width at half maximum (FWHM) at around 0.08° (288 arcsec). These findings contribute to the understanding of the preparation of high-quality β-(AlxGa1−x)2O3 films on sapphire substrates.

© 2024 The Royal Society of Chemistry. (50 refs.)