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A 4Ă—4 beta-phase gallium oxide (β -Ga2O3) deep-ultraviolet (DUV) rectangular 10-fingers interdigital metal-semiconductor-metal (MSM) photodetector array of high photo responsivity is introduced. The Ga2O3 thin film is prepared through the metalorganic chemical vapor deposition technique, then used to construct the photodetector array via photolithography, lift-off, and ion beam sputtering methods. The one photodetector cell shows dark current of 1.94 pA, photo-to-dark current ratio of 6Ă—107, photo responsivity of 634.15 Aâ‹...Wâˆ'1, specific detectivity of 5.93Ă—1011 cmâ‹...Hz1/2â‹...Wâˆ'1 (Jones), external quantum efficiency of 310000%, and linear dynamic region of 108.94 dB, indicating high performances for DUV photo detection. Furthermore, the 16-cell photodetector array displays uniform performances with decent deviation of 19.6% for photo responsivity. [ABSTRACT FROM AUTHOR]

In this work, a solar-blind ultraviolet (UV) photodetector based on a three-terminal enhancement-mode (E-mode) Si-doped β -Ga2O3 (β -Ga2O3:Si) metal-semiconductor field-effect transistor structure is demonstrated, whose threshold voltage (V th) and subthreshold swing are 4.04 V and 1.4 V decâˆ'1, respectively. A 400 nm thick β -Ga2O3:Si thin film is prepared on sapphire substrate by using metal-organic chemical vapor deposition method. Controlling the channel currents by the Schottky gate voltage in the dark and under illuminations, the photodetector shows dark current (I dark) as low as 13.4 pA, photo-to-dark current ratio of 4.85 Ă— 104 and linear dynamic range of 29.6 dB, illuminated by 254 nm UV light of 245 ÎĽ W cmâˆ'2. As the UV light is turned on and off, the output current rise and decay time (Ď„ r and Ď„ d) are 420 ms and 350 ms. Moreover, at drain voltage (V ds) of 5 V and gate voltage (V gs) of 0 V, the responsivity (R), specific detectivity (D*) and external quantum efficiency are achieved as 74 A Wâˆ'1, 2.15 Ă— 1014 cm Hz1/2 Wâˆ'1 (Jones) and 3.6 Ă— 104%, respectively. [ABSTRACT FROM AUTHOR]

In this article, a 16 × 4 linear array of β-Ga2O3-based metal-semiconductor-metal structured photodetector is described for solar-blind sensing operation at a wavelength of 254 nm. The β-Ga2O3 film is grown by using metal-organic chemical vapor deposition (MOCVD) equipment, and the photodetectors are finished in constructing with standard photolithography and ion beam sputtering procedures. The results show that the dark current (Idark), photo-to-dark current ratio (PDCR), photo responsivity (R), specific detectivity (D*), exterl quantum efficiency (EQE), and linear dynamic region (LDR) are 1.94 pA, 2.95 × 107, 139.56 A/W, 2.55 × 1015 Jones, 6.8 × 104 %, and 149.4 dB, at 10 V bias and 2000 μW/cm2 light intensity illumination. In addition, the standard deviation of R for this photodetector array is 10%. Overall, such a 16 × 4 linear array of β-Ga2O3-based photodetector array makes a progress in the field of Ga2O3 photodetectors. [ABSTRACT FROM AUTHOR]

In this work, through chemical vapor deposition (CVD) method, almost indistinguishable planar rose-like ZnO (PRZ) nanostructures could be prepared on the surface of honeycombed gallium nitride (HGaN) after more than ten deposition tests, and then constructed into PRZ/HGaN heterojunction gas sensor. Subsequent gas behaviors showed that the PRZ/HGaN heterostructure constructed by CVD greatly improved the selectivity and response value (32.5 at 100 ppm) to H 2 , and realized the improvement of the H 2 sensing performance without noble metal modification. Importantly, fast response and recovery time was 47 s and 6 s, respectively. Meanwhile, this sensor presented excellent selectivity and stability. Ultimately, the dynamic monitoring of the sensor was performed for five consecutive months, and the fluctuation ratio of the response value (sensitivity) did not exceed ±2%. It could be predicted that the as-obtained sensor was expected to promote the substantial process of industrialization of highly stable metal oxide/HGaN heterojunction sensors. • Planar rose-like ZnO (PRZ) was synthesized by chemical vapor deposition (CVD) method. • Honeycombed gallium nitride (HGaN) acted as an acceptor for electron transferred during sensor operation. • The PRZ/HGaN heterojunction effectively improved the weak selectivity of mixed gas. • The morphology evolution of the PRZ caused by the adjustment of the deposition distance in the tube furnace. [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]

Herein, a CuSCN/Ga 2 O 3 heterojunction device was fabricated by spin-coating and metal-organic chemical vapor deposition (MOCVD) methods. Under the irradiation of 254 nm deep ultraviolet (DUV) light with an intensity of 1000 μ W/cm 2 , the device shown high sensitivity and favorable self-powered performances with photo-to-dark current ratio (PDCR) of 1.29 × 10 4 , photo responsivity (R) of 5.5 mA/W, rejection ratio (R 270nm / R 600nm) of 4.33 × 10 3 , and specific detectivity (D ∗) of 3.8 × 10 11 cm Hz 1/2 W − 1 (Jones) at − 5 V. In addition, the device has a rise time of 0.45 s and 3.80 s, and a decay time of 0.26 s and 0.26 s. In general, the CuSCN/Ga 2 O 3 heterojunction prepared in this work may well be a potential candidate for achieving a self-powered and high-performance DUV photodetector. • A p-CuSCN/n-Ga 2 O 3 thin film heterojunction is constructed for performing DUV detection. • Under the irradiation of 254 nm DUV light with an intensity of 1000 μ W/cm2, at bias of -5 V, the device shown good performances. • The heterojunction photodetector could operate at zero bias. [ABSTRACT FROM AUTHOR]