Ultra-wide Bandgap Semiconductor Research Articles

Directional Carrier Transport in Micrometer-Thick Gallium Oxide Films for High-Performance Deep-Ultraviolet Photodetection.

Incorporating emerging ultrawide bandgap semiconductors with a metal-semiconductor-metal (MSM) architecture is highly desired for deep-ultraviolet (DUV) photodetection. However, synthesis-induced defects in semiconductors complicate the rational design of MSM DUV photodetectors due to their dual role as carrier donors and trap centers, leading to a commonly observed trade-off between responsivity and response time. Here, we demonstrate a simultaneous improvement of these two parameters in ε-Ga2O3 MSM photodetectors by establishing a low-defect diffusion barrier for directional carrier transport. Specifically, using a micrometer thickness far exceeding its effective light absorption depth, the ε-Ga2O3 MSM photodetector achieves over 18-fold enhancement of responsivity and simultaneous reduction of the response time, which exhibits a state-of-the-art photo-to-dark current ratio near 108, a superior responsivity of >1300 A/W, an ultrahigh detectivity of >1016 Jones, and a decay time of 123 ms. Combined depth-profile spectroscopic and microscopic analysis reveals the existence of a broad defective region near the lattice-mismatched interface followed by a more defect-free dark region, while the latter one serves as a diffusion barrier to assist frontward carrier transport for substantially enhancing the photodetector performance. This work reveals the critical role of the semiconductor defect profile in tuning carrier transport for fabricating high-performance MSM DUV photodetectors.

PyGWBSE: a high throughput workflow package for GW-BSE calculations

We develop an open-source python workflow package, pyGWBSE to perform automated first-principles calculations within the GW-BSE (Bethe-Salpeter) framework. GW-BSE is a many body perturbation theory based approach to explore the quasiparticle (QP) and excitonic properties of materials. GW approximation accurately predicts bandgaps of materials by overcoming the bandgap underestimation issue of the more widely used density functional theory (DFT). BSE formalism produces absorption spectra directly comparable with experimental observations. pyGWBSE package achieves complete automation of the entire multi-step GW-BSE computation, including the convergence tests of several parameters that are crucial for the accuracy of these calculations. pyGWBSE is integrated with Wannier90, to generate QP bandstructures, interpolated using the maximally-localized wannier functions. pyGWBSE also enables the automated creation of databases of metadata and data, including QP and excitonic properties, which can be extremely useful for future material discovery studies in the field of ultra-wide bandgap semiconductors, electronics, photovoltaics, and photocatalysis.

Exploration and investigation of stable novel Al2O3 by high-throughput screening and density functional theory

The graph and group theory based random strategy (RG2) code is employed to obtain three stable Al2O3 polymorphs (P21/c, Pnma-I, and Pnma-II Al2O3) are obtained based on high-throughput screening and density functional theory. The three Al2O3 polymorphs have dynamic stability, mechanical stability, and thermal stability and can remain thermally stable at least up to 2000 K. As the pressure increases, P21/c Al2O3 changes to CaIrO3-type Al2O3 at ∼75–80 GPa. The electronic band structures show that the three polymorphs are all ultrawide band gap semiconductor materials with band gaps of 5.74–6.40 eV, and P21/c Al2O3 has a direct band gap. The B/G values of P21/c and Pnma-I Al2O3 are greater than 1.75, which confirms that they are ductile. They may have potential application in optoelectronic material, microelectronic material, and thermal barrier coating materials.

Secondary electron emission and vacuum electronics

Secondary electron emission serves as the foundation for a broad range of vacuum electronic devices and instrumentation, from particle detectors and multipliers to high-power amplifiers. While secondary yields of at least 3–4 are required in practical applications, the emitter stability can be compromised by surface dynamics during operation. As a result, the range of practical emitter materials is limited. The development of new emitter materials with high yield and robust operation would advance the state-of-the-art and enable new device concepts and applications. In this Perspective article, I first present an analysis of the secondary emission process, with an emphasis on the influence of material properties. From this analysis, ultra-wide bandgap (UWBG) semiconductors and oxides emerge as superior emitter candidates owing to exceptional surface and transport properties that enable a very high yield of low-energy electrons with narrow energy spread. Importantly, exciting advances are being made in the development of promising UWBG semiconductors such as diamond, cubic boron nitride (c-BN), and aluminum nitride (AlN), as well as UWBG oxides with improved conductivity and crystallinity. These advances are enabled by epitaxial growth techniques that provide control over the electronic properties critical to secondary electron emission, while advanced theoretical tools provide guidance to optimize these properties. Presently, H-terminated diamond offers the greatest opportunity because of its thermally stable negative electron affinity (NEA). In fact, an electron amplifier under development exploits the high yield from this NEA surface, while more robust NEA diamond surfaces are demonstrated with potential for high yields in a range of device applications. Although c-BN and AlN are less mature, they provide opportunities to design novel heterostructures that can enhance the yield further.

Call for Papers for a Special Issue of IEEE Transactions on Electron Devices on "Wide and Ultrawide Band Gap Semiconductor Devices for RF and Power Applications"

Call for Papers for a Special Issue of IEEE Transactions on Electron Devices on "Wide and Ultrawide Band Gap Semiconductor Devices for RF and Power Applications"

Wide and Ultrawide Band Gap Semiconductor Devices for RF and Power Applications

Wide and Ultrawide Band Gap Semiconductor Devices for RF and Power Applications

Call for Papers for a Special Issue of IEEE Transactions on Electron Devices on "Wide and Ultrawide Band Gap Semiconductor Devices for RF and Power Applications"

Call for Papers for a Special Issue of IEEE Transactions on Electron Devices on "Wide and Ultrawide Band Gap Semiconductor Devices for RF and Power Applications"

Ultra-Wide Band Gap Ga2O3-on-SiC MOSFETs.

Ultra-wide band gap semiconductor devices based on β-phase gallium oxide (Ga2O3) offer the potential to achieve higher switching performance and efficiency and lower manufacturing cost than that of today's wide band gap power electronics. However, the most critical challenge to the commercialization of Ga2O3 electronics is overheating, which impacts the device performance and reliability. We fabricated a Ga2O3/4H-SiC composite wafer using a fusion-bonding method. A low-temperature (≤600 °C) epitaxy and device processing scheme was developed to fabricate MOSFETs on the composite wafer. The low-temperature-grown epitaxial Ga2O3 devices deliver high thermal performance (56% reduction in channel temperature) and a power figure of merit of (∼300 MW/cm2), which is the highest among heterogeneously integrated Ga2O3 devices reported to date. Simulations calibrated based on thermal characterization results of the Ga2O3-on-SiC MOSFET reveal that a Ga2O3/diamond composite wafer with a reduced Ga2O3 thickness (∼1 μm) and a thinner bonding interlayer (<10 nm) can reduce the device thermal impedance to a level lower than that of today's GaN-on-SiC power switches.

The anisotropy dependence of deformation mechanism of cleavage planes in β-Ga2O3 single crystal

β-Ga2O3 is a promising ultra-wide bandgap semiconductor. The deformation of β-Ga2O3 was few investigations, especially on the cleavage planes which hindered the high-efficiency and low-damage manufacturing of β-Ga2O3 wafers. Here, the anisotropy dependence of mechanical response and deformation mode of the (100) and (001) cleavage planes in β-Ga2O3 single crystal were studied by the nanoindentation method. The results showed that a broad deformation zone was formed on the subsurface of the β-Ga2O3 wafer after unloading, which was dominated by slippage, dislocations, stacking faults, and cracks. Cross stacking faults were found on the subsurface of the (100) plane. Under the same load condition, the damaged zone depth of the (001) plane was twice that of the (100) plane. At the same time, two kinds of cracks with different angles were found on the subsurface. The direction of the crack is related to stress distribution. The crack propagation mechanism transitioned to brittle cleavage fracture within the loading process. The crack did not extend to the indentation surface of the (100) plane. These results revealed the mechanism of deformation and damage in the manufacturing of low-symmetry β-Ga2O3 wafers.

Ultrawide bandgap willemite-type Zn2GeO4 epitaxial thin films

Willemite-type Zn2GeO4 is a promising ultrawide bandgap semiconductor material. To date, experimental results on growth and physical properties of epitaxial thin films of willemite-type Zn2GeO4 are not available. Here, we report the heteroepitaxial growth of (00.1)-oriented Zn2GeO4 thin films on c-plane sapphire substrates using pulsed laser deposition. The in-plane orientation relationships are [11.0] Zn2GeO4//[11.0] Al2O3 and [11¯.0] Zn2GeO4//[11¯.0] Al2O3. A 450 nm thick epitaxial film with a surface roughness of 2.5 nm deposited under 0.1 mbar oxygen partial pressure exhibits a full width at half maximum (FWHM) of rocking curve of (00.6) reflex of 0.35°. The direct bandgap is evaluated to be 4.9 ± 0.1 eV. The valence band maximum is determined to be 3.7 ± 0.1 eV below the Fermi level. Together with the density-functional theory band structure calculation, it is suggested that the O 2p orbital and Zn 3d orbital dominantly contribute to the valence band of Zn2GeO4. The steady-state photoluminescence (PL) spectra of the films under 266 nm excitation at room temperature exhibit a broad defect-related emission band centered at 2.62 eV with a FWHM of 0.55 eV. The origin of this native defect-related PL is suggested to correlate with Zn interstitials. This work advances the fundamental study on willemite-type Zn2GeO4 epitaxial thin films for potential device application.

Investigation of properties of Ta-doped Ga2O3 films prepared with seed layers

Ga2O3 is a promising ultra-wide bandgap semiconductor as a feasible candidate for power electronics, photodetectors, and sensors. Controlling electrical properties through doping is the key to its application in semiconductor devices. In this work, Ta-doped Ga2O3 films were prepared by radio frequency (RF) magnetron sputtering with seed layers. Effects of the thickness of seed layers on the microstructure, morphology, optical and electrical properties of Ta-doped Ga2O3 films were investigated. The fabricated Ta-doped Ga2O3 films exhibited polycrystalline structure with uniform and smooth surface and high optical transmittance (＞80 %) in the visible light region. The results showed that seed layers with appropriate thickness (∼20 nm) is beneficial to the improvement of crystalline quality and electrical properties of Ta-doped Ga2O3 films.

Toward achieving cost-effective hexagonal BN semi-bulk crystals and BN neutron detectors via halide vapor phase epitaxy

Presently, thermal neutron detectors fabricated from boron-10 enriched hexagonal boron nitride (h-10BN) ultrawide bandgap semiconductor grown by metal organic chemical vapor deposition (MOCVD) hold the record high detection efficiency among all solid-state detectors at 59%. To overcome the short comings of MOCVD growth, including inherently low growth rate and unavoidable impurities such as carbon in metal organic source, we demonstrate here the growth of natural hexagonal boron nitride (h-BN) semi-bulk wafers using halide vapor phase epitaxy (HVPE), which is an established technique for producing GaN semi-bulk crystals at a high growth rate. Electrical transport characterization results revealed that these HVPE grown materials possess an electrical resistivity of 1 × 1013 Ω cm, and a charge carrier mobility and lifetime product of 2 × 10−4 cm2/V s. Detectors fabricated from a 100 μm thick h-BN wafer have demonstrated a thermal neutron detection efficiency of 20%, corresponding to a charge collection efficiency of ∼60% at an operating voltage of 500 V. This initial demonstration opens the door for mass producing high efficiency h-BN semiconductor neutron detectors at a reduced cost, which could create unprecedented applications in nuclear energy, national security, nuclear waste monitoring and management, the health care industry, and material sciences.

Two-dimensional InTeClO3: an ultrawide-bandgap material with potential application in a deep ultraviolet photodetector.

Ultrawide-bandgap semiconductors, possessing bandgaps distinctly larger than the 3.4 eV of GaN, have emerged as a promising class capable of achieving deep ultraviolet (UV) light detection. Based on first-principles calculations, we propose an unexplored two-dimensional (2D) InTeClO3 layered system with ultrawide bandgaps ranging from 4.34 eV of bulk to 4.54 eV of monolayer. Our calculations demonstrate that 2D InTeClO3 monolayer can be exfoliated from its bulk counterpart and maintain good thermal and dynamic stability at room temperature. The ultrawide bandgaps may be modulated by the small in-plane strains and layer thickness in a certain range. Furthermore, the 2D InTeClO3 monolayer shows promising electron transport behavior and strong optical absorption capacity in the deep UV range. A two-probe InTeClO3-based photodetection device has been constructed for evaluating the photocurrent. Remarkably, the effective photocurrent (5.7 A m-2 at photon energy of 4.2 eV) generation under polarized light has been observed in such a photodetector. Our results indicate that 2D InTeClO3 systems have strong photoresponse capacity in the deep UV region, accompanying the remarkable polarization sensitivity and high extinction ratio. These distinctive characteristics highlight the promising application prospects of InTeClO3 materials in the field of deep UV optoelectronics.

Preparation and ultraviolet detection performance of Cu doped &lt;i&gt;β&lt;/i&gt;-Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; thin films

Solar-blind UV photodetectors (SBPs) have attracted great attention because they are widely used in missile tracking, fire detection, biochemical analysis, astronomical observations, space-to-space communications, etc. At present, it is found that wide bandgap semiconductor materials such as Al&lt;sub&gt;&lt;i&gt;x&lt;/i&gt;&lt;/sub&gt;Ga&lt;sub&gt;1-&lt;i&gt;x&lt;/i&gt;&lt;/sub&gt;N, Mg&lt;sub&gt;1&lt;/sub&gt;Zn&lt;sub&gt;1-&lt;i&gt;x&lt;/i&gt;&lt;/sub&gt;O, diamond and &lt;i&gt;β&lt;/i&gt;-Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; are ideal semiconductor materials for developing high-performance SBPs. The ultra-wide band gap semiconductor material, &lt;i&gt;β&lt;/i&gt;-Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;, has a large band gap width of 4.9 eV, strong breakdown electric field, absorption edge located in the solar blind ultraviolet band (200–280 nm), and it also has high transmittance in the near ultraviolet and the whole visible band. Therefore, &lt;i&gt;β&lt;/i&gt;-Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; is a very suitable material for making solar blind UV photodetectors. However, the p-type &lt;i&gt;β&lt;/i&gt;-Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; is difficult to dope, which limits the further development of &lt;i&gt;β&lt;/i&gt;-Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; devices. In this work, the &lt;i&gt;β&lt;/i&gt;-Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; thin films with different Cu doping content are grown on sapphire substrates by chemical vapor deposition method, and the morphology, crystal structure and optical properties of &lt;i&gt;β&lt;/i&gt;-Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; films are measured. The test results show that the surfaces of &lt;i&gt;β&lt;/i&gt;-Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; films with different Cu content are relatively smooth, and the (&lt;inline-formula&gt;&lt;tex-math id="M2"&gt;\begin{document}$ \bar 201 $\end{document}&lt;/tex-math&gt;&lt;alternatives&gt;&lt;graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="19-20230971_M2.jpg"/&gt;&lt;graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="19-20230971_M2.png"/&gt;&lt;/alternatives&gt;&lt;/inline-formula&gt;) diffraction peak positions shift toward the lower degree side with the increase of Cu content, which indicates that Cu&lt;sup&gt;2+&lt;/sup&gt; replaces Ga&lt;sup&gt;3+&lt;/sup&gt; and enters into the &lt;i&gt;β&lt;/i&gt;-Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; lattice. The optical absorption spectrum measurement indicates that the energy gaps of samples are evidently narrowed with the increase of Cu doping concentration. Hall measurements indicate that the Cu doped &lt;i&gt;β&lt;/i&gt;-Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; thin films have a p-type conductivity with a hole concentration of 7.36 × 10&lt;sup&gt;14&lt;/sup&gt;, 4.83 × 10&lt;sup&gt;15&lt;/sup&gt; and 1.69 × 10&lt;sup&gt;16 &lt;/sup&gt;cm&lt;sup&gt;–3&lt;/sup&gt;, respectively. In addition, a photoconductive UV detector with metal-semiconductor-metal structure is prepared by evaporating Au on a Cu-doped &lt;i&gt;β&lt;/i&gt;-Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; thin film, and its UV detection performance is studied. The results show that the photocurrent value of the device increases with Cu content increasing. The photo-to-dark current ratio (&lt;i&gt;I&lt;/i&gt;&lt;sub&gt;l&lt;/sub&gt;/&lt;i&gt;I&lt;/i&gt;&lt;sub&gt;d&lt;/sub&gt;) is about 3.8×10&lt;sup&gt;2&lt;/sup&gt; of 2.4% Cu content device under 254 nm-wavelength light at 10 V. The rise time and decay time are 0.11 s and 0.13 s, respectively. Furthermore, the responsivity and external quantum efficiency can reach 1.72 A/W and 841% under 254 nm-wavelength light with a light intensity of 64 μW/cm&lt;sup&gt;2&lt;/sup&gt;.

Call for Papers for a Special Issue of IEEE Transactions on Electron Devices on “Wide and Ultrawide Band Gap Semiconductor Devices for RF and Power Applications”

Call for Papers for a Special Issue of IEEE Transactions on Electron Devices on “Wide and Ultrawide Band Gap Semiconductor Devices for RF and Power Applications”

Wide and Ultrawide Band Gap Semiconductor Devices for RF and Power Applications

Wide and Ultrawide Band Gap Semiconductor Devices for RF and Power Applications

Call for Papers for a Special Issue of IEEE Transactions on Electron Devices on "Wide and Ultrawide Band Gap Semiconductor Devices for RF and Power Applications"

Call for Papers for a Special Issue of IEEE Transactions on Electron Devices on "Wide and Ultrawide Band Gap Semiconductor Devices for RF and Power Applications"

Broadband ultrafast photogenerated carrier dynamics induced by intrinsic defects in &lt;inline-formula&gt;&lt;tex-math id="Z-20231102113631"&gt;\begin{document}$\boldsymbol\beta$\end{document}&lt;/tex-math&gt;&lt;alternatives&gt;&lt;graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="21-20231173_Z-20231102113631.jpg"/&gt;&lt;graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="21-20231173_Z-20231102113631.png"/&gt;&lt;/alternatives&gt;&lt;/inline-formula&gt;-Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;

The ultra-wide bandgap semiconductor gallium oxide &lt;i&gt;β&lt;/i&gt;-Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; with enhanced resistance to the irradiation and temperature is favorable for high-power and high-temperature optoelectronic devices. &lt;i&gt;β&lt;/i&gt;-Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; also exhibits great potential applications in the field of integrated photonics because of its compatibility with the CMOS technique. However, a variety of intrinsic and extrinsic defects and trap states coexist in &lt;i&gt;β&lt;/i&gt;-Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;, including vacancies, interstitials, and impurity atoms. The defect-related carrier dynamics in &lt;i&gt;β&lt;/i&gt;-Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; not only adversely affect the optical and electrical properties, but also directly limit the performance of &lt;i&gt;β&lt;/i&gt;-Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; based devices. Therefore, a comprehensive understanding of the carrier transportation and relaxation dynamics induced by intrinsic defects is very important. Supercontinuum-probe spectroscopy can provide a fruitful information about the carrier relaxation processes in different recombination mechanisms, and thus becomes an effective way to study the defect dynamics. In this work, we study the dynamics of carrier trapping and recombination induced by intrinsic defects in pristine &lt;i&gt;β&lt;/i&gt;-Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; crystal by using wavelength-tunable ultrafast transient absorption spectroscopy. The broadband absorption spectra induced by the intrinsic defects are strongly dependent on the polarization of pump pulse and probe pulse. Particularly, two absorption peaks induced by the two defect states can be extracted from the transient absorption spectra by subtracting the absorption transients under two probe polarizations. The observed defect-induced absorption features are attributed to the optical transitions from the valence band to the different charge states of the intrinsic defects (such as gallium vacancy). The data are well explained by a proposed carrier capture model based on multi-level energies. Moreover, the hole capture rate is found to be much greater than that of the electron, and the absorption cross-section of the defect state is at least 10 times larger than that of free carrier. Our findings not only clarify the relationship between intrinsic defects and photogenerated carrier dynamics, but also show the importance in the application of &lt;i&gt;β&lt;/i&gt;-Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; crystals in ultrafast and broadband photonics.

Characterization of boron-doped single-crystal diamond by electrophysical methods (review)

A critical analysis of the existing methods of controlling the concentration of impurity and majority charge carriers in wide bandgap semiconductors and the issues of improvement of modern diagnostics of the main electrophysical properties of single-crystal diamond are considered based on the results of our studies and the works of other authors. It was found that independent assessment of impurity concentration and concentration of free charge carriers is of fundamental importance for semiconductor diamond due to very low (less than 1%) degree of ionization of the introduced impurity. The advantages and prospects of admittance spectroscopy as a diagnostic method for ultrawide bandgap semiconductors are shown and solutions aimed at the correct interpretation of the experimental data are proposed. The high ionization energy of boron impurity in diamond (370 meV) results in a strong frequency dispersion of the measured barrier capacitance. It is shown that under disturbance of quasi-static conditions in capacitance-voltage measurements, low frequencies and high temperatures should be used for correct assessment of the charge carrier concentration. The results of electrophysical studies are compared with traditional measurements of impurity concentration in diamond by optical methods. A decrease of hole activation energy from the boron impurity level from 325 to 100 meV was found upon increasing the boron concentration NA from 2·1016 to 4·1019 cm-3. The transition to the hopping mechanism of conductivity within the impurity (acceptor) band with thermal activation energy of 10-20 meV was registered for NA≥5·1018 cm-3 at temperatures of 120-150 K. Keywords: single-crystal diamond, boron impurity, charge carrier concentration, activation energy, admittance spectroscopy, capacitance-voltage measurements.

Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;-based metal-insulator-semiconductor solar-blind ultraviolet photodetector with HfO&lt;sub&gt;2&lt;/sub&gt; inserting layer

Solar-blind photodetector (PD) converts 200–280 nm ultraviolet (UV) light into electrical signals, thereby expanding application range from security communication to missile or fire alarms detections. As an emerging ultra-wide bandgap semiconductor, gallium oxide (Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;) has sprung to the forefront of solar blind detection activity due to its key attributes, including suitable optical bandgap, convenient growth procedure, highly temperture/chemical/radiation tolerance, and thus becoming a promising candidate to break the current bottleneck of photomultiplier tubes. The Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;-based solar blind PDs based on various architectures have been realized in the past decade, including photoconductive PDs, Schottky barrier PDs, and avalanche PDs. Till now, the metal-semiconductor-metal (MSM) structure has been widely used in developing photoconductive Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; solar-blind PDs because of its simple preparation method and large light collection area. Unfortunately, despite unremitting efforts, the performance metric of reported MSM-type Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; solar-blind PDs still lags behind the benchmark of commercial PMTs. Apparently, lack of solution to the problem has greatly hindered further research and practical applications in this field. One effective strategy for further enhancing the device performance such as detectivity, external quantum efficiency (EQE), and light-to-dark ratio heavily relies on blocking the dark current. In this work, high-quality single crystalline &lt;i&gt;β&lt;/i&gt;-Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; with a uniform thickness of 700 nm is grown by using a metal organic chemical vapor deposition (MOCVD) technique. Then atomic layer deposition (ALD) fabricated ultrathin hafnium oxide (HfO&lt;sub&gt;2&lt;/sub&gt;) films (&lt;inline-formula&gt; &lt;tex-math id="Z-20230428020102-1"&gt;\begin{document}$ \sim $\end{document}&lt;/tex-math&gt;&lt;alternatives&gt;&lt;graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="9-20222222_Z-20230428020102-1.jpg"/&gt;&lt;graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="9-20222222_Z-20230428020102-1.png"/&gt;&lt;/alternatives&gt;&lt;/inline-formula&gt;10 nm) are introduced as inserted insulators and passivation layers. The 30 nm/100 nm Ti/Au interdigital electrodes (length: 2800 μm, width: 200 μm, spacing: 200 μm, 4 pairs) are fabricated by sputtering on the top of the film as the Ohmic contacts. Taking advantage of its novel dielectric and insulating properties, the leakage current on Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; thin film can be effectively inhibited by the inserted ultrathin HfO&lt;sub&gt;2&lt;/sub&gt; layer, and thus further improving the performance of PDs. Compared with simple MSM structured Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; PD, the resulting metal-insulator-semiconductor (MIS) device significantly reduces dark current, and thus improving specific detectivity, enhancing light-to-dark current ratio, and increasing response speed. These findings advance a significant step toward the suppressing of dark current in MSM structured photoconductive PDs and provide great opportunities for developing high-performance weak UV signal sensing in the future.