Polarization-Sensitive Solar-Blind Ultraviolet Photodetectors Based on Semipolar (112̅2) AlGaN Film

Area of Science:

• Materials Science
• Optoelectronics
• Semiconductor Physics

Background:

• Wide bandgap semiconductor aluminum gallium nitride (AlGaN) alloys are crucial for solar-blind ultraviolet photodetectors (SBUV PDs).
• Semipolar AlGaN offers unique properties for advanced device applications.
• Developing self-driven devices eliminates the need for external power sources.

Purpose of the Study:

• To report a self-driven SBUV polarization-sensitive photodetector (PSPD) based on semipolar (112̅2)-oriented AlGaN films.
• To investigate the material properties and device performance of semipolar AlGaN for UV detection.
• To explore the potential of AlGaN-based PSPDs in multifunctional optoelectronic devices.

Main Methods:

• Epitaxial growth of semipolar (112̅2)-oriented AlGaN films using flow-rate modulation epitaxy.
• Characterization of crystal quality using high-resolution X-ray diffraction (HRXRD).
• Density functional theory (DFT) calculations and experimental measurements to analyze in-plane anisotropy and photoresponse.

Main Results:

• Achieved state-of-the-art heteroepitaxial semipolar AlGaN with narrow rocking curve FWHMs (0.205° and 0.262°).
• Demonstrated a self-driven (112̅2) AlGaN PSPD with strong polarization sensitivity (ratio of 1.54 at 266 nm) and rapid response (450/450 ms).
• Observed unique positive and negative photoresponse behaviors attributed to surface states and charge transfer.

Conclusions:

• Semipolar AlGaN is a promising material for high-performance SBUV PSPDs.
• The developed PSPD exhibits excellent polarization sensitivity and fast response times.
• The findings open possibilities for multifunctional SBUV optoelectronic devices with tailored functionalities.