Pulsed laser deposition grown non-stoichiometry transferred ZnGa2O4 films for deep-ultraviolet applications

Yen, Ching Yu; Singh, Anoop Kumar; Chang, Hsun; Chang, Kai-Ping; Chen, Po‐Wei; Liu, Po−Liang; Wuu, Dong−Sing

doi:10.1016/j.apsusc.2022.153700

Cited by 19 publications

(8 citation statements)

References 42 publications

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“…In addition, the F-points at (2π/ a ) (0,1/2,0) are the intersections with the zone surface along the six equivalent <010> directions, where a is the lattice constant. The band structures of the oxide-passivation ZGO surface and the oxide-passivation ZGO surface with one surface oxygen removed are shown in Figure 12 a,b, which represent direct band gaps of 2.73 eV and 2.77 eV, respectively, which closely match the other theoretical gap of the ZGO bulk of 2.82 eV and severely underestimate the experimental band gap of 5.18 eV for the ZGO bulk due to the well-known shortcomings of the strong hybridization of inner electrons [ 39 , 40 , 41 ]. Note also that the appearance of a defect level in the forbidden bandgap is caused by the removal of one surface oxygen atom.…”

Section: Resultsmentioning

confidence: 56%

Structure Effect on the Response of ZnGa2O4 Gas Sensor for Nitric Oxide Applications

et al. 2022

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We fabricated a gas sensor with a wide-bandgap ZnGa2O4 (ZGO) epilayer grown on a sapphire substrate by metalorganic chemical vapor deposition. The ZGO presented (111), (222) and (333) phases demonstrated by an X-ray diffraction system. The related material characteristics were also measured by scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. This ZGO gas sensor was used to detect nitric oxide (NO) in the parts-per-billion range. In this study, the structure effect on the response of the NO gas sensor was studied by altering the sensor dimensions. Two approaches were adopted to prove the dimension effect on the sensing mechanism. In the first approach, the sensing area of the sensors was kept constant while both channel length (L) and width (W) were varied with designed dimensions (L × W) of 60 × 200, 80 × 150, and 120 ×100 μm2. In the second, the dimensions of the sensing area were altered (60, 40, and 20 μm) with W kept constant. The performance of the sensors was studied with varying gas concentrations in the range of 500 ppb~10 ppm. The sensor with dimensions of 20 × 200 μm2 exhibited a high response of 11.647 in 10 ppm, and 1.05 in 10 ppb for NO gas. The sensor with a longer width and shorter channel length exhibited the best response. The sensing mechanism was provided to explain the above phenomena. Furthermore, the reaction between NO and the sensor surface was simulated by O exposure of the ZGO surface in air and calculated by first principles.

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Section: Resultsmentioning

confidence: 56%

Structure Effect on the Response of ZnGa2O4 Gas Sensor for Nitric Oxide Applications

et al. 2022

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“…where D represents the grain size of the films, K represents a constant (0.9), λ represents the wavelength of the incident Xray beam source, β represents the fwhm of the intense peak of the (222) crystalline plane, β 0 signifies instrumental broadening, and θ represents the Bragg diffraction angle. 9 Initially, at 400 °C, the films exhibit a relatively large grain size of 67.42 nm. However, as the annealing temperature is increased to 600 °C and further to 900 °C, the grain size decreases considerably to 45.86 nm.…”

Section: Resultsmentioning

confidence: 99%

“…The ZnGa 2 O 4 spinel exhibits cubic symmetry with the Fd 3̅ m space group, where oxygen atoms are densely packed in a cubic arrangement and cation atoms are arranged in a face-centered cubic pattern. Although ZnGa 2 O 4 possesses a wide band gap and has the capacity to absorb deep ultraviolet (<280 nm) light, exhibiting its potential for applications in deep ultraviolet light sensors, flame detection, ozone layer monitoring, and optical communication, ,− its transistor characteristics remain unexplored. The ample band gap of the ZnGa 2 O 4 material endows it with the capability to withstand high breakdown voltages, showcasing outstanding chemical and thermal stability.…”

Section: Introductionmentioning

confidence: 99%

Growth and Performance Enhancement of Sputtered ZnGa₂O₄ MOSFETs on Sapphire Substrates

Singh,

Yen,

Huang

et al. 2024

ACS Appl. Electron. Mater.

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Metal-oxide-semiconductor field-effect transistors (MOSFETs) based on wide-band-gap semiconductors have garnered significant attention for their potential in high-performance and energy-efficient electronic devices. In this study, we explore the low-temperature growth, characterization, and performance of ZnGa2O4 film based MOSFETs on sapphire substrates through the utilization of radio frequency (RF) magnetron sputtering. The characteristics of ZnGa2O4 films were meticulously investigated at various annealing temperatures, specifically 400, 600, and 900 °C. Our findings revealed that the crystallinity of ZnGa2O4 films was notably superior at a low annealing temperature of 400 °C. Subsequently, we fabricated MOSFET devices by patterning the ZnGa2O4 films to create gate, source, and drain regions using a conventional photolithography process. The electrical characteristics of the ZnGa2O4 MOSFETs were thoroughly examined, unveiling their operation in the depletion mode. These devices exhibited a threshold voltage of −5 V, a maximum drain current of 110 mA/mm, a remarkable high drain current on–off current ratio of 107, and an excellent breakdown voltage of 575 V, underlining their suitability for high-power applications. This research demonstrates the successful fabrication of ZnGa2O4 based depletion-mode MOSFETs using a sputtering technique, offering a pathway toward the development of next-generation electronic devices with enhanced performance.

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“…S2 shows that the atomic ratio of Zn, Ga, and O is 1:2:4, which is the same as the stoichiometric ratio, meaning that the stoichiometric ZnGa 2 O 4 film was fabricated by the PLD. 32) Meanwhile, some inside holes and cracks are observed from the crosssectional SEM images. To eliminate these defects, other samples were fabricated by increasing the substrate temperature to 600 °C (the annealing conditions were kept unchanged).…”

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“…The presence of weak diffraction and spurious signals in the films can be observed, which is consistent with the EDS findings. 32) Figure 3(a) shows the absorption spectra of ZnGa 2 O 4 grown on Al 2 O 3 substrate before and after annealing. It is observed that the cut-off absorption edge is blue-shifted from 300 to 240 nm after annealing, which indicates that annealing can effectively reduce the formation of amorphous and improve the crystalline quality of the film.…”

mentioning

confidence: 99%

Pulsed laser deposition of ZnGa₂O₄ thin films on Al₂O₃ and Si substrates for deep optoelectronic devices applications

Guo¹,

Zhang²,

Cao³

et al. 2023

Appl. Phys. Express

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Due to the ultra-wide bandgap, high transmittance in the ultraviolet (UV) region, and excellent environmental stability, zinc gallium oxide (ZnGa2O4) has attracted considerable interest in deep-ultraviolet (DUV) photodetectors. Here, ZnGa2O4 thin films were fabricated on different substrates by PLD with a post-annealing process under an oxygen atmosphere. It is found that the substrates have great impact on the morphology, structure, and crystal quality of thin films. After annealing, the thin film quality has been improved. The metal semiconductor-metal (MSM) photodetector shows excellent reproducible characteristics and fast response performance, which demonstrates great potential in the next-generation optoelectronic devices.

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Pulsed laser deposition grown non-stoichiometry transferred ZnGa2O4 films for deep-ultraviolet applications

Cited by 19 publications

References 42 publications

Structure Effect on the Response of ZnGa2O4 Gas Sensor for Nitric Oxide Applications

Structure Effect on the Response of ZnGa2O4 Gas Sensor for Nitric Oxide Applications

Growth and Performance Enhancement of Sputtered ZnGa₂O₄ MOSFETs on Sapphire Substrates

Pulsed laser deposition of ZnGa₂O₄ thin films on Al₂O₃ and Si substrates for deep optoelectronic devices applications

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Pulsed laser deposition grown non-stoichiometry transferred ZnGa2O4 films for deep-ultraviolet applications

Cited by 19 publications

References 42 publications

Structure Effect on the Response of ZnGa2O4 Gas Sensor for Nitric Oxide Applications

Structure Effect on the Response of ZnGa2O4 Gas Sensor for Nitric Oxide Applications

Growth and Performance Enhancement of Sputtered ZnGa2O4 MOSFETs on Sapphire Substrates

Pulsed laser deposition of ZnGa2O4 thin films on Al2O3 and Si substrates for deep optoelectronic devices applications

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Product

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Growth and Performance Enhancement of Sputtered ZnGa₂O₄ MOSFETs on Sapphire Substrates

Pulsed laser deposition of ZnGa₂O₄ thin films on Al₂O₃ and Si substrates for deep optoelectronic devices applications