Surface-Engineered Nanostructure-Based Efficient Nonpolar GaN Ultraviolet Photodetectors

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Gallium nitride (GaN)-based photodetectors (PDs) are crucial for ultraviolet (UV) applications.
• Improving the performance and reliability of GaN UV PDs remains a key research area.

Purpose of the Study:

• To engineer the surface of nonpolar (112̅0) GaN films to create nanostructures.
• To investigate the impact of surface engineering on the performance of GaN-based UV PDs.

Main Methods:

• Fabrication of surface-engineered nanostructured nonpolar GaN films.
• Modification of surface morphology from pyramidal to trigonal nanorods using wet chemical etching.
• Fabrication of metal-semiconductor-metal (MSM) structure-based UV PDs.

Main Results:

• Achieved a 5.5-fold enhancement in photocurrent and a 6-fold increase in responsivity.
• Significantly improved detectivity from 0.43 to 2.83 (×10⁸) Jones.
• Demonstrated faster switching speeds (332 ms response, 995 ms decay) compared to unetched devices.
• Observed a very low noise-equivalent power (∼10^-10 W Hz^-1/2).

Conclusions:

• Wet chemical etching-induced surface engineering effectively enhances GaN UV PD performance.
• The nanostructured surface improves light absorption and carrier transport, reducing defect-related recombination.
• This approach offers a promising pathway for developing high-performance GaN-based photodetector technology.