Effect of off-axis substrate angles on β-Ga2O3 thin films and solar-blind ultraviolet photodetectors grown on sapphire by MOCVD

Ma, Yongjian; Tang, Wenbo; Chen, Tiwei; Zhang, Li; He, Tao; Zhou, Xin; Wei, Xing; Deng, Xuguang; Fu, Houqiang; Xu, Kun; Zhang, Xiaodong; Zhang, Baoshun

doi:10.1016/j.mssp.2021.105856

Cited by 23 publications

(14 citation statements)

References 34 publications

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“…PDs based on c-plane and Δ a -plane sapphire (Δ a -plane sapphire refers to sapphire with an off-axis angle of 6°toward ⟨112̅ 0⟩) with the NPSL are labeled as S 2 and S 4 , respectively, while S 1 and S 3 represent PDs fabricated on c-plane and Δ a -plane sapphire without an NPSL for reference, respectively. Based on our previous work 44 and related reports, 45 Δ a -plane sapphire can suppress the multiple orientations of the β-Ga 2 O 3 and subsequently reduce the dislocations. The effects of the NPSL on the crystal structure and crystallinity of Ga 2 O 3 thin films were investigated by an X-ray diffractometer (XRD).…”

Section: ■ Results and Discussionmentioning

confidence: 83%

High-Speed and Ultrasensitive Solar-Blind Ultraviolet Photodetectors Based on In Situ Grown β-Ga₂O₃ Single-Crystal Films

Chen,

Zhang,

Zhang

et al. 2024

ACS Appl. Mater. Interfaces

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Deep-level defects in β-Ga 2 O 3 that worsen the response speed and dark current (I d ) of photodetectors (PDs) have been a long-standing issue for its application. Herein, an in situ grown single-crystal Ga 2 O 3 nanoparticle seed layer (NPSL) was used to shorten the response time and reduce the I d of metal−semiconductor-metal (MSM) PDs. With the NPSL, the I d was reduced by 4 magnitudes from 0.389 μA to 81.03 pA, and the decay time (τ d1 /τ d2 ) decreased from 258/1690 to 62/142 μs at −5 V. In addition, the PDs with the NPSL also exhibit a high responsivity (43.5 A W −1 ), high specific detectivity (2.81 × 10 14 Jones), and large linear dynamic range (61 dB) under 254 nm illumination. The mechanism behind the performance improvement can be attributed to the suppression of the deep-level defects (i.e., self-trapped holes) and increase of the Schottky barrier. The barrier height extracted is increased by 0.18 eV compared with the case without the NPSL. Our work contributes to understanding the relationship between defects and the performance of PDs based on heteroepitaxial β-Ga 2 O 3 thin films and provides an important reference for the development of high-speed and ultrasensitive deep ultraviolet PDs.

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Section: ■ Results and Discussionmentioning

confidence: 83%

High-Speed and Ultrasensitive Solar-Blind Ultraviolet Photodetectors Based on In Situ Grown β-Ga₂O₃ Single-Crystal Films

Chen,

Zhang,

Zhang

et al. 2024

ACS Appl. Mater. Interfaces

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“…36–38 Therefore, the (2̄01) preferential growth of β-Ga 2 O 3 was always reported in the heteroepitaxial growth of β-Ga 2 O 3 on c -sapphire. 2–5,9,13,17,23,24,29,31,39 Under Ga-rich conditions, Ga atoms would not have sufficient time to migrate to the most suitable crystallographic sites. It is possible that Ga atoms initially preferentially form the Ga I –O bonds with O atoms on the surface of the (0001) α-Al 2 O 3 substrate, then form the Ga II –O bonds (as can be seen in Fig.…”

Section: Resultsmentioning

confidence: 99%

(3̄10)-Oriented β-Ga₂O₃ grown on (0001) sapphire by halide vapor phase epitaxy: growth and structural characterizations

Xu,

Li,

et al. 2023

CrystEngComm

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“…Recently, several approaches have been proposed to obtain high-quality 𝛽-Ga 2 O 3 thin films to improve PD performance. [13][14][15] Although highly crystalline thin films would effectively suppress dark current (I dark ), the decreased internal gain limits the photocurrent (I light ). Consequently, the strategy for implementing high-performance UV PD relies heavily on enhancing charge generation and separation while blocking the leakage current.…”

Section: Introductionmentioning

confidence: 99%

Enhancing Performance of Ultraviolet C Photodetectors Through Single‐Domain Epitaxy of Monoclinic β‐Ga₂O₃ Films and Tailored Anti‐Reflection Coating

Kim,

Lee

et al. 2023

Small Methods

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Implementing high‐performance ultraviolet C photodetectors (UVC PDs) based on β‐Ga2O3 films is challenging owing to the anisotropic crystal symmetry between the epitaxial films and substrates. In this study, highly enhanced state‐of‐the‐art photoelectrical performance is achieved using single‐domain epitaxy of monoclinic β‐Ga2O3 films on a hexagonal sapphire substrate. Unlike 3D β‐Ga2O3 films with twin domains, 2D β‐Ga2O3 films exhibit a single domain with a smooth surface and low concentration of point defects, which enable efficient charge separation by suppressing boundary‐induced recombination. Furthermore, a tailored anti‐reflection coating (ARC) is adopted as a light‐absorbing medium to improve charge generation. The tailored nanostructure, which features a gradient refractive index, not only substantially reduces the reflection, but also suppresses the surface leakage current as a passivation layer. This study provides fundamental insights into the single‐domain epitaxy of β‐Ga2O3 films and the application of ARC for the development of high‐performance UVC PDs.

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Effect of off-axis substrate angles on β-Ga2O3 thin films and solar-blind ultraviolet photodetectors grown on sapphire by MOCVD

Cited by 23 publications

References 34 publications

High-Speed and Ultrasensitive Solar-Blind Ultraviolet Photodetectors Based on In Situ Grown β-Ga₂O₃ Single-Crystal Films

High-Speed and Ultrasensitive Solar-Blind Ultraviolet Photodetectors Based on In Situ Grown β-Ga₂O₃ Single-Crystal Films

(3̄10)-Oriented β-Ga₂O₃ grown on (0001) sapphire by halide vapor phase epitaxy: growth and structural characterizations

Enhancing Performance of Ultraviolet C Photodetectors Through Single‐Domain Epitaxy of Monoclinic β‐Ga₂O₃ Films and Tailored Anti‐Reflection Coating

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Effect of off-axis substrate angles on β-Ga2O3 thin films and solar-blind ultraviolet photodetectors grown on sapphire by MOCVD

Cited by 23 publications

References 34 publications

High-Speed and Ultrasensitive Solar-Blind Ultraviolet Photodetectors Based on In Situ Grown β-Ga2O3 Single-Crystal Films

High-Speed and Ultrasensitive Solar-Blind Ultraviolet Photodetectors Based on In Situ Grown β-Ga2O3 Single-Crystal Films

(3̄10)-Oriented β-Ga2O3 grown on (0001) sapphire by halide vapor phase epitaxy: growth and structural characterizations

Enhancing Performance of Ultraviolet C Photodetectors Through Single‐Domain Epitaxy of Monoclinic β‐Ga2O3 Films and Tailored Anti‐Reflection Coating

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Product

Resources

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High-Speed and Ultrasensitive Solar-Blind Ultraviolet Photodetectors Based on In Situ Grown β-Ga₂O₃ Single-Crystal Films

High-Speed and Ultrasensitive Solar-Blind Ultraviolet Photodetectors Based on In Situ Grown β-Ga₂O₃ Single-Crystal Films

(3̄10)-Oriented β-Ga₂O₃ grown on (0001) sapphire by halide vapor phase epitaxy: growth and structural characterizations

Enhancing Performance of Ultraviolet C Photodetectors Through Single‐Domain Epitaxy of Monoclinic β‐Ga₂O₃ Films and Tailored Anti‐Reflection Coating