β-phase gallium oxide (β-Ga2O3) is attracting attention as a deep—ultraviolet photodetector (PD) owing to its large band gap of 4.9 eV, almost direct band gap characteristics, and solar-blind photodetection. However, most Ga2O3-based transistor-type PDs operate in a normally-on mode. In this study, a silicon (Si)-doped β-Ga2O3 epilayer with normally-off characteristics was grown on a nitrogen (N)-doped buffer layer of a c-plane Al2O3 substrate using metal–organic chemical vapor deposition. The N-doped layer acts as a buffer layer during Si-doped β-Ga2O3 growth and improves crystallinity. In addition, the N-doped buffer layer has semi-insulating properties that reduce leakage current, enabling precise control of the effective thickness of the Si-doped β-Ga2O3 epilayer. Phototransistors are fabricated to improve the characteristics of ultraviolet PDs, such as photo-to-dark current ratio and on–off time. The Si-doped β-Ga2O3-based transistor-type PD has a detectivity of 3.85 × 1016 Jones at a wavelength of 260 nm. It achieves detectivity values similar to those of flake-based PDs, and performs the best amongst non-flake-based PDs. Moreover, its rising time and decay time are 3.8 ms and 3.5 ms, respectively; these are among the smallest values reported for existing Ga2O3-based transistor-type PDs. The fabricated epilayer will facilitate the fabrication of high-performance and efficient photo-electronic devices.

中文翻译：

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在 N 掺杂 β-Ga2O3 上生长的高性能常闭 Si 掺杂 β-Ga2O3 深紫外光电晶体管


β相氧化镓 （β-Ga2O3） 因其 4.9 eV 的大带隙、几乎直接的带隙特性和日盲光探测而作为深紫外光电探测器 （PD） 而备受关注。然而，大多数基于 Ga2O3 的晶体管型 PD 在常开模式下运行。在这项研究中，使用金属-有机化学气相沉积在 c 面 Al2O3 衬底的氮 （N） 掺杂缓冲层上生长了具有常闭特性的硅 （Si） 掺杂 β-Ga2O3 外延层。N 掺杂层在 Si 掺杂 β-Ga2O3 生长过程中充当缓冲层，并提高结晶度。此外，N 掺杂缓冲层具有半绝缘特性，可降低泄漏电流，从而能够精确控制 Si 掺杂 β-Ga2O3 外延层的有效厚度。制造光电晶体管是为了改善紫外局部放电的特性，例如光暗电流比和开关时间。基于 Si 掺杂 β-Ga2O3 的晶体管型 PD 在 260 nm 波长下的探测率为 3.85 × 1016 Jones。它实现了与基于片状的 PD 相似的检测率值，并且在非基于片状的 PD 中表现最佳。此外，其上升时间和衰减时间分别为 3.8 ms 和 3.5 ms;这些是现有基于 Ga2O3 的晶体管型 PD 报告的最小值之一。制造的外延层将有助于制造高性能和高效的光电器件。