Qian Feng

This work systematically investigates the heteroepitaxial growth of β-Ga₂O₃ thin films under varied substrate and temperature conditions via metalorganic chemical vapor deposition (MOCVD). Comprehensive characterization reveals that both the substrate type and growth temperature significantly influence the crystalline quality, surface morphology, chemical composition, and defect structure. Films grown at higher temperatures generally exhibit superior crystallinity and closer-to-stoichiometry composition, and thus suggest a reduction in oxygen deficiency. Certain substrates are shown to facilitate high-quality epitaxial growth with smooth surfaces and excellent crystallographic alignment. These findings offer key insights into optimizing growth parameters for high-performance β-Ga₂O₃-based devices.

This study explores Sn-doped Ga2O3 thin films synthesized via the double-pulse metalorganic chemical vapor deposition (MOCVD) method, highlighting its unique advantages in improving film microstructure and electrical properties. The results show that the double-pulse Sn-doped technique, through intermittent atomic supply, promotes medium-range ordering of Sn atoms within the Ga2O3 lattice, reducing lattice defects and enhancing crystallinity. Secondary ion mass spectrometry further reveals a doping activation rate of 95%. Notably, the films exhibit exceptional electrical performance, achieving a Hall mobility of 175.61 cm2/V·s at a carrier concentration of 2.17 × 1018 cm−3. This value represents a record-high mobility for β-Ga2O3 at this carrier concentration, significantly surpassing the performance of films prepared via conventional continuous deposition methods. This study offers valuable insights into the mechanisms of double-pulse MOCVD and its potential for Ga2O3-based high-performance electronic devices, providing an effective pathway for optimizing next-generation electronic materials.

In this work, β-Ga₂O₃ based Schottky barrier diodes (SBDs) with a composite termination structure of the ZnNiO thin alloy films are reported. β-Ga₂O₃ SBDs with the junction termination extension structure of the wide-bandgap p-type ZnNiO achieve a breakdown voltage (V_br) of 2040 V and a specific on-resistance R_on,sp of 3.48 mΩ·cm², contributing a power figure of merit (PFOM, V_br ²/R_on,sp) of 1.20 GW cm⁻². Meanwhile, we demonstrated high-performance vertical β-Ga₂O₃ SBDs with the bevel junction termination extension (BJTE) structure, which the R_on,_sp,V_br and BFOM are 4.21 mΩ·cm², 2704 V, and 1.74 GW cm⁻², respectively. Technology computer aided design simulations show that BJTE structure significantly optimizes the surface electric field of β-Ga₂O₃ drift layer. These devices make a significant step to achieve high performance β-Ga₂O₃ power devices by implementing a composite termination structure.

In this work, we demonstrated a high-performance NiO/ $\beta$ -Ga $_{\text{2}}$ O $_{\text{3}}$ heterojunction photodetector using piranha solution pretreatment technology. After treatment, the NiO/ $\beta$ -Ga $_{\text{2}}$ O $_{\text{3}}$ heterojunction exhibited an excellent electrical performance, including a higher on/off ratio of 1 $\times$ 10 $^{\text{7}}$ , a lower reverse current of 0.28 pA, and an improved ideal factor. Additionally, the solar-blind detection performance of treated sample was significantly enhanced, including a 2900% increase in photo-to-dark-current ratio (PDCR), a 140% increase in responsivity, and a 900% increase in detectivity. Notably, excellent rise time and decay time were observed to be 60 and 50 ms after treatment, demonstrating an impressive reduction of 97% and 98%, respectively. This fast response characteristic has a wide range of applications. Thus, we conducted an optical communication test based on an original solar-blind communication system. Data transmission was successfully achieved ten times with a short sampling time of 100 ms. These results illustrate the effectiveness of piranha solution pretreatment in elevating the performance of Ga $_{\text{2}}$ O $_{\text{3}}$ -based heterojunction photodetector.

In this work, we report on achieving enhanced performance NiO $_{\textit{x}}$ /beta gallium oxide ( $\beta $ -Ga $_{\text{2}}$ O $_{\text{3}}$ ) heterojunction p-n diodes (HJDs) through synergistic interface engineering (SIE), which can greatly improve the electrical characteristics and interface characteristics of HJDs. It is shown that the NiO $_{\textit{x}}$ surface undergoes morphological improvement and hole concentration enhancement after the UV/ozone treatment (UVO). Owing to the improved interfacial properties of Ni/NiO $_{\textit{x}}$ , the forward conduction current of NiO $_{\textit{x}}$ / $\beta $ -Ga $_{\text{2}}$ O $_{\text{3}}$ HJD has significantly increased. Furthermore, the HJD performance can be improved by SIE with UVO and postannealing, especially for the reverse breakdown characteristics. Finally, a high-performance HJD without any terminal structure is obtained, which exhibits a low specific on-resistance of 2.47 m $\Omega \cdot$ cm $^{\text{2}}$ and a high breakdown voltage of 1355 V, yielding a high Baliga’s figure of merit (BFOM) of 0.743 GW/cm $^{\text{2}}$ , which is a 219.17% enhancement in performance compared to untreated device. This work offers a practical and effective strategy for developing advanced Ga $_{\text{2}}$ O $_{\text{3}}$ devices with exceptional performance metrics, paving the way for future technological breakthroughs.

This article innovatively uses pulsed metal-organic chemical vapor deposition technology to optimize the quality of β-Ga2O3 thin films on (−201) β-Ga2O3 homo-substrate using indium pulse-assisted technology. The results demonstrate that the pulsed indium-assisted method, when compared with the traditional indium-assisted method, effectively suppresses the desorption of Ga2O, enhances the flatness of the β-Ga2O3 film, and reduces the surface roughness from 34.8 to 0.98 nm. The optimized single crystalline β-Ga2O3 film was grown with pulsed-indium, and the full width at half maximum of x-ray diffraction rocking curve was 30.42 arc sec, smaller than that of the continuous indium β-Ga2O3 (56.1 arc sec). In combination with the x-ray photoelectron spectroscopy O1s split-peak fitting analysis, the relative content of oxygen vacancies in the film was significantly reduced by pulsed indium-assisted method. The Hall mobility of films assisted by pulsed-indium is approximately 14 times higher than that of films assisted by traditional indium. The pulsed indium technology provides an idea for homoepitaxial growth of high-quality β-Ga2O3 films.

In this paper, the radiation effect of gamma irradiation (60Co) on the Au/Ni/β-Ga2O3 vertical Schottky barrier diodes (SBDs) was investigated for total doses of about 1 Mrad (Si). The SBDs were characterized by current density–voltage (J–V) and capacitance–voltage (C–V) measurements. Compared with original β-Ga2O3 SBDs, it was found that Schottky barrier height Φb increases from 1.08 to 1.12 eV, the ideality factor n decreases from 1.07 to 1.02, and the specific on-resistance Ron,sp decreases from 3.34 to 2.95 mΩ·cm2 for the irradiated β-Ga2O3 SBDs. In addition, the carrier concentration calculated from the C–V measurements increases slightly after gamma irradiation. The temperature-dependent current–voltage characteristics and conductance-frequency measurements indicate that the Schottky contact interface of β-Ga2O3 SBDs had been slightly improved after irradiation. These results suggest that β-Ga2O3 SBDs have high intrinsic gamma irradiation hardness.

In this work, we demonstrated the enhancement mode (E-mode) β-Ga2O3 metal–oxide–semiconductor field-effect transistor (MOSFET) by introducing a hybrid floating gate (HFG) structure. This E-mode Ga2O3 MOSFET featured the highest VTH of 9.03 V and the highest maximum current ID of 70.0 mA/mm among the reported lateral normally off β-Ga2O3 MOSFETs. Meanwhile, a breakdown voltage of 834 V, a specific on-resistance RON,sp of 19.3 mΩ·cm2, and a sub-threshold swing SS of 87 mV/dec were achieved simultaneously. In addition, VTH shifted by only 9.9% after applying a gate stress of 25 V for 105 s. These findings provide a promising path for the development of enhancement-mode Ga2O3 power devices by incorporating a charge-storage structure.