Photonic-Electronic Dual-Passivated Ultrafast β-Ga₂O₃ SBUV Photodiode

Area of Science:

• Materials Science
• Optoelectronics
• Semiconductor Physics

Background:

• Ultrafast response is crucial for solar-blind ultraviolet (SBUV) photodetectors (PDs) used in applications such as fault warning and aircraft exhaust plume monitoring.
• Existing SBUV PDs often face limitations in response speed due to carrier diffusion and surface trapping-detrapping dynamics.
• Gallium oxide (β-Ga2O3) is a promising material for SBUV PDs due to its wide bandgap and intrinsic properties.

Purpose of the Study:

• To develop a novel strategy for enhancing the response speed of β-Ga2O3-based SBUV PDs.
• To mitigate carrier diffusion and surface trapping-detrapping effects in SBUV PDs.
• To achieve ultrafast response times and excellent overall performance at zero bias.

Main Methods:

• Proposed a novel photonic-electronic dual-passivation (PEDP) strategy.
• Applied the PEDP strategy to β-Ga2O3-based SBUV PDs.
• Characterized the performance of PEDP-modified PDs, including rise time, decay time, dark current, photo-to-dark current ratio, rejection ratio, responsivity, and external quantum efficiency.

Main Results:

• Achieved an ultrafast rise time of 5.9 ns and decay time of 86.8 ns at 0 V bias.
• Demonstrated performance exceeding existing SBUV PDs by 2-9 orders of magnitude in terms of speed.
• Obtained excellent performance at 0 V bias: dark current of 0.58 pA, photo-to-dark current ratio of 5.04 × 10^4, rejection ratio (R200 nm/R350 nm) of 1.12 × 10^4, responsivity of 0.084 A W^-1, and external quantum efficiency of 59.9%.

Conclusions:

• The photonic-electronic dual-passivation (PEDP) strategy is effective in achieving ultrafast response for β-Ga2O3-based SBUV PDs.
• The PEDP strategy successfully mitigates carrier diffusion and surface trapping-detrapping dynamics.
• This work provides valuable insights for developing advanced fast-response SBUV detection and imaging technologies.