In this Letter, 4-inch diameter (100) magnesium-doped monoclinic gallium oxide (Mg:β-GaO) bulk single crystals were grown by a casting method. The crystallographic structure, electrical, optical properties, and defects of Mg-doped β-GaO was thoroughly investigated by XRD rocking curves, AFM, non-contact resistivity measurements, XPS, optical transmission spectra, Raman spectroscopy, and defect-selective chemical etching processes. Comparing to the UID samples, the larger bandgap of 4.75 eV and high resistivity of 3.50×10 Ω∙cm indicated Mg a proper dopant for fabricating semi-insulating β-GaO substrates which could be preferred for power devices. XPS spectra exhibited the ability of Mg to inhibit the formation of oxygen vacancy defects in the crystals. Meanwhile, the high crystalline quality and low density of defects demonstrated the advantages of casting method in achieving large-size and high-quality β-GaO bulk single crystals with changeable resistivity. This result indicates a high potential to achieve high-quality and low-cost substrates which satisfy the requirement of high-performance power electronic devices.

中文翻译：

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铸造法生长的4英寸（100）取向Mg掺杂β-Ga2O3块状单晶的特性

在这封信中，通过铸造方法生长了直径 4 英寸（100）的镁掺杂单斜氧化镓（Mg:β-GaO）块状单晶。通过 XRD 摇摆曲线、AFM、非接触电阻率测量、XPS、光学透射光谱、拉曼光谱和缺陷选择性化学蚀刻工艺，彻底研究了 Mg 掺杂 β-GaO 的晶体结构、电学、光学性质和缺陷。与 UID 样品相比，4.75 eV 的较大带隙和 3.50×10 Ω·cm 的高电阻率表明 Mg 是制造半绝缘 β-GaO 衬底的合适掺杂剂，可用于功率器件。 XPS 光谱显示 Mg 抑制晶体中氧空位缺陷形成的能力。同时，高晶体质量和低缺陷密度显示了铸造法在获得大尺寸、高质量、电阻率可变的β-GaO块体单晶方面的优势。这一结果表明实现满足高性能电力电子器件要求的高质量和低成本衬底的巨大潜力。