The band alignment between oxygen plasma-assisted atomic layer deposition Al₂O₃ films and β-Ga₂O₃ (−201) substrates under different deposition temperatures was characterized by x-ray photoelectron spectroscopy. As the deposition temperature increased from 30 to 200 °C, all the heterojunctions exhibited a type-I alignment. The bandgap of Al₂O₃ enlarged from 6.26 ± 0.1 to 6.81 ± 0.1 eV, leading to the conduction band offset varying linearly from 1.39 ± 0.1 to 1.95 ± 0.1 eV, while the valence band offset was insensitive. This difference was attributed to Al ion deficiency and hydroxyl groups induced by an inadequate reaction of trimethylaluminum under low deposition temperatures, which was proved by secondary ion mass spectrometry (SIMs) and Fourier-transform infrared spectroscopy (FTIR). These findings could facilitate the design of a CBO-controllable Al₂O₃/β-Ga₂O₃ heterojunction through deposition temperature.

中文翻译：

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沉积温度对原子层沉积制备的Al2O3 /β-Ga2O3异质结界面的能带取向调制

通过X射线光电子能谱表征了在不同沉积温度下氧等离子体辅助原子层沉积Al ₂ O ₃膜与β- Ga ₂ O ₃（-201）衬底之间的能带对准。随着沉积温度从30°C升高到200°C，所有异质结均表现出I型排列。Al ₂ O ₃的带隙从6.26±0.1 eV扩大到6.81±0.1 eV，导致导带偏移从1.39±0.1到1.95±0.1 eV线性变化，而价带偏移不敏感。这种差异归因于三甲基铝在低沉积温度下反应不足引起的Al离子缺乏和羟基，这已通过二次离子质谱（SIM）和傅里叶变换红外光谱（FTIR）得以证明。这些发现可能有助于CBO可控Al的设计₂ ö ₃ /的β-Ga ₂ ö ₃异质结通过沉积温度。