β-Ga₂O₃ thin films have been successfully prepared on (0001) sapphire substrate by simple and effective sol-gel spin-coating method with post-annealing process (SSP). The effects of different preheating temperatures on the crystal quality and surface morphology of β-Ga₂O₃ films have been systematically investigated. The β-Ga₂O₃ thin films exhibit good crystallinity with (\(\bar 2\)01) preferred orientation and smooth surface morphology. The results showed that β-Ga₂O₃ thin films directly grown on (0001) sapphire by SSP method have comparable or better crystal quality compared with other epitaxial methods. The β-Ga₂O₃ thin films annealed at 1000 °C with the preheating temperature of 300 °C and above have smooth and crack-free surface morphology. The single-domain-growth mode of β-Ga₂O₃ thin film prepared on ~7° off-angled (0001) sapphire substrate toward <11\(\bar 2\)0> plane has been confirmed by SSP method, and the porous GaN layers have been obtained by the nitridation of the Sol-Gel grown β-Ga₂O₃ thin films for future applications in high-quality free-standing GaN substrates.

β-Ga ₂ O ₃薄膜已通过简单有效的溶胶-凝胶旋涂法和后退火工艺（SSP）成功地制备在（0001）蓝宝石衬底上。系统研究了不同预热温度对β-Ga ₂ O ₃薄膜晶体质量和表面形貌的影响。β-Ga ₂ O ₃薄膜表现出良好的结晶度，具有( \(\bar 2\) 01) 择优取向和光滑的表面形态。结果表明，β-Ga ₂ O ₃与其他外延方法相比，通过 SSP 方法直接在 (0001) 蓝宝石上生长的薄膜具有相当或更好的晶体质量。β-Ga ₂ O ₃薄膜在1000℃下退火，预热温度为300℃及以上，具有光滑无裂纹的表面形貌。β-Ga ₂ O ₃薄膜在~7°斜角（0001）蓝宝石衬底上向<11 \(\bar 2\) 0> 平面制备的单畴生长模式已通过SSP方法得到证实，并且多孔 GaN 层是通过溶胶-凝胶生长的 β-Ga ₂ O ₃薄膜的氮化获得的，用于未来在高质量独立式 GaN 衬底中的应用。