Solar-Blind Enhanced Dual-Band Ultraviolet Photodetector

Area of Science:

• Materials Science
• Optoelectronics
• Semiconductor Physics

Background:

• Gallium Oxide (Ga2O3) and Gallium Nitride (GaN) are wide-bandgap semiconductors with potential for UV optoelectronic devices.
• Achieving high-performance solar-blind UV photodetectors with dual-band capabilities remains a challenge.

Purpose of the Study:

• To develop a dual-band ultraviolet photodetector with enhanced solar-blind performance.
• To utilize varying current relaxation rates for distinguishing different UV wavelengths.
• To suppress persistent photoconductivity in UV photodetectors.

Main Methods:

• Fabrication of a beta-Gallium Oxide/(Aluminum Gallium Oxide)/Gallium Nitride heterojunction.
• Characterization of the photodetector's response under different UV wavelengths and biases.
• Analysis of current relaxation dynamics and persistent photoconductivity suppression techniques.

Main Results:

• The heterojunction photodetector demonstrated enhanced solar-blind UV detection.
• A photocurrent gain of 2033, photoresponsivity of 900 A/W, and detectivity of 2.55 × 10^13 Jones were achieved.
• The device successfully distinguished between UV wavelengths (λ ≤ 270 nm and λ > 270 nm) based on current relaxation rates.
• Persistent photoconductivity was suppressed by combining UV illumination with circuit interruption.

Conclusions:

• The developed Ga2O3/(AlxGa1-x)2O3/GaN heterojunction is a promising candidate for dual-band solar-blind UV detection.
• The strategy of utilizing differential current relaxation rates offers a novel approach for wavelength discrimination.
• The device exhibits excellent performance metrics, including high gain, responsivity, and detectivity in the solar-blind UV range.