High Performance GaN-Based Ultraviolet Photodetector via Te/Metal Electrodes

Area of Science:

• Materials Science
• Optoelectronics
• Semiconductor Devices

Background:

• Two-dimensional (2D) material photodetectors (PDs) face challenges like low responsivity and slow response speeds due to carrier recombination and surface trapping.
• Gallium Nitride (GaN) is a promising material for photodetectors, but its performance is often limited by contact resistance and interface issues.

Purpose of the Study:

• To develop a high-performance GaN-based photodetector with enhanced photoresponse and speed.
• To investigate the effect of Tellurium (Te) as an electrode material on GaN photodetector characteristics.

Main Methods:

• Fabrication of a GaN-based photodetector on a sapphire substrate using Te/metal electrodes.
• Characterization of the photodetector's responsivity, detectivity, external quantum efficiency, and response time.
• Analysis of the Te/GaN interface properties and their impact on carrier transport.

Main Results:

• The Te-enhanced GaN PD achieved a high responsivity of 4951 mA/W and detectivity of 1.79 × 10¹⁴ Jones.
• An external quantum efficiency of 169% was recorded, indicating efficient light conversion.
• The Te/GaN interface significantly reduced response time compared to pure GaN PDs by facilitating carrier collection and forming ohmic-like contacts.

Conclusions:

• Tellurium enhances GaN photodetector performance by reducing contact resistance and improving carrier transport through the formation of an inherent electric field at the Te/GaN interface.
• This approach offers a new strategy for developing high-performance photodetectors.
• The findings expand the application potential of GaN in advanced optoelectronic devices.