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In this study, 2-in. wafer-scale large-area β-Ga2O3 epitaxial films were fabricated on c-plane sapphire substrates via metal-organic chemical vapor deposition. X-ray diffraction, atomic force microscopy, field-emission scanning electron microscope, and photoelectric properties were carried out to disclose the material uniformity of large-scale β-Ga2O3 epitaxial films. Even with film thickness as thick as 1.5 μm, the grown β-Ga2O3 epitaxial films demonstrated high crystal quality with an average FWHM of 1.71° and a standard deviation (SD) of 0.035, smooth surface morphology with an average root-mean-square of 5.45 nm and a slight deviation of 0.09 nm, outstanding thickness uniformity with an average film thickness of 1.55 μm and SD value of only 28 nm. Furthermore, each β-Ga2O3 photodetector on epitaxial wafer expressed uniform stability of the photoelectric performance distribution. High material uniformity of our fabricated large-scale β-Ga2O3 epitaxial films lays a solid foundation for its future mass production of Ga2O3-based devices. [ABSTRACT FROM AUTHOR]

Doping technology with stable carrier concentration regulation is a guarantee for optimizing β -Ga 2 O 3 -based high-power electronic devices and optoelectronic devices. In this study, β -Ga 2 O 3 homoepitaxial epitaxial films with stable and tunable electron concentrations were grown on Fe-doped (010)-oriented β -Ga 2 O 3 substrates by using metal-organic chemical vapor deposition (MOCVD). XRD shows that the basic bulk properties of β -Ga 2 O 3 film, i. e. the structure and crystal orientation, are stable with low Si-doping, however, its electrical properties vary remarkably depending on concentrations of Si ions incorporated by Si source flow rate during the film growth process. Hall measurement is utilized to confirm high-quality β -Ga 2 O 3 films with tunable electron concentration of 1017–1019 cm−3. As a consequence, the electron concentration-dependent behavior of β -Ga 2 O 3 Schottky barrier diodes (SBDs) was studied. The β -Ga 2 O 3 SBDs exhibited better forward current output electrical performance with reduction in built-in potential difference (V bi) from 2.4 V to 0.3 V and on-resistance (R on) from 257 Ω cm to 26 Ω cm. Our results suggest that stable and tunable electron concentration provides high-quality material assurance for constructing power electronic devices of Ga 2 O 3. • We achieved high-quality β -Ga 2 O 3 films with tunable electron concentrations of 1017–1019 cm−3 by using MOCVD. • We constructed high-performance lateral β -Ga 2 O 3 SBDs with tunable electronic properties. • The doped films exhibit good forward current output characteristics and a relatively fast current growth rate. [ABSTRACT FROM AUTHOR]

The influences of low growth temperatures (420–490 °C) on phase transition of Ga 2 O 3 films grown on Al 2 O 3 substrates by means of metal-organic chemical vapor deposition (MOCVD) are investigated here. The changes of crystal structure, phase composition, surface and cross-sectional morphologies are carried out by X-ray diffraction, atomic force microscope and field-emission scanning electron microscope to reveal the detail evolution from ε -phase to β -phase in Ga 2 O 3 films. The fluctuant Gibbs free energy change relying on growth temperature induces different growth mechanism of Ga 2 O 3 films. Furthermore, the ultraviolet photoresponse properties of different phase compositions for Ga 2 O 3 films are compared by constructing metal-semiconductor-metal photodetectors. It is found that mixture phase Ga 2 O 3 films express better photodetection performance than pure phase Ga 2 O 3 films due to the formation of built-in field within phase junction. This proposed regulation principle of Ga 2 O 3 phase transition provides a new route to high-performance photoelectric material. • Phase transition from ε -Ga 2 O 3 to β -Ga 2 O 3 was captured in a low growth temperature window of 420–490 °C by MOCVD. • Different Ga 2 O 3 phase compositions resulted in varying crystal structures, surface morphologies and UV sensing properties. • Ga 2 O 3 films with mixture phases demonstrated better photoresponse due to the formation of built-in field within phase junction. [ABSTRACT FROM AUTHOR]

• A β-Ga 2 O 3 /CuBiI 4 heterojunction deep-ultraviolet photodetector was constructed. • The fabricated device exhibited responsivity of 20.68 A/W and detectivity of 3.72 × 1015 Jones. • The detector could display self-powered operation. Herein, a β-Ga 2 O 3 /CuBiI 4 heterojunction deep-ultraviolet (DUV) photodetector was constructed based on metal-organic chemical vapor deposition grown β-Ga 2 O 3 film and spin-coated CuBiI 4 film. In which, we prepared the pure and well-crystallized CuBiI 4 film from environment-friendly materials under optimized experimental conditions. The fabricated device exhibited a large responsivity of 20.68 A/W, a high specific detectivity of 3.72 × 1015 Jones, a high photo-to-dark current ratio of 5.62 × 106, a low dark current of 0.385 pA, and an ultrahigh UV/visible rejection ratio (R 250 nm / R 400 nm) of 1.14 × 104 under 254 nm UV light illumination at 5 V. In all, the device can sensitively monitor a wide range of UV light (254 nm) intensities from 0.1 to 2000 μW/cm2. Moreover, the potential of the device operating under self-powered mode has been verified, and the intrinsic physical mechanism of the heterojunction photodetector was analyzed via energy-band alignment. Overall, this work would present a promising route to realize high-performance and cost-effective DUV photodetector. [ABSTRACT FROM AUTHOR]