Solar-blind photodetector based on LaAlO3 with low dark current

Area of Science:

• Materials Science
• Optoelectronics
• Semiconductor Physics

Background:

• Metal-semiconductor-metal (MSM) photodetectors are crucial for detecting ultraviolet (UV) radiation.
• Developing solar-blind photodetectors with low dark current and high responsivity is essential for various applications.
• LaAlO3 (110) substrates offer unique properties for advanced device fabrication.

Purpose of the Study:

• To fabricate and characterize a solar-blind photodetector on LaAlO3 (110) substrates.
• To investigate the performance of platinum (Pt) and gold (Au) electrodes in MSM photodetectors.
• To understand the factors contributing to low dark current and high responsivity in these devices.

Main Methods:

• Fabrication of MSM photodetectors using Pt and Au electrodes on LaAlO3 (110) substrates.
• Material characterization using X-ray Diffraction (XRD) and UV-visible absorption spectroscopy.
• Electrical and optical performance testing of the photodetector devices under UV illumination.

Main Results:

• The photodetector with Pt electrodes exhibited a significantly lower dark current (4.1 pA) compared to Au electrodes (14.6 pA) at 10 V bias.
• A peak responsivity of 32.5 mA/W was achieved at 200 nm, within the solar-blind spectral region (200-280 nm).
• Low dark current is attributed to high surface step/facet density and lattice mismatch at the Pt/LaAlO3 interface.

Conclusions:

• Pt electrodes on LaAlO3 (110) substrates are superior for fabricating low-dark-current solar-blind photodetectors.
• The device demonstrates excellent performance for solar-blind UV detection applications.
• Further research can optimize fabrication for enhanced photodetector characteristics.