Thickness-Induced Crystal Orientation Regulation in a Magnetron-Sputtered GaSb Buffer Layer for High-Performance...

Area of Science:

• Materials Science
• Semiconductor Physics
• Optoelectronics

Background:

• Indium Arsenide/Gallium Antimonide (InAs/GaSb) heterostructures are crucial for high-performance infrared detection.
• Low-cost, high-quality film fabrication is essential for widespread InAs/GaSb photodetector (PD) application.

Purpose of the Study:

• To investigate the effects of magnetron sputtering parameters on InAs/GaSb film growth.
• To optimize fabrication for high-performance, room-temperature InAs/GaSb PDs.

Main Methods:

• Systematic investigation of magnetron sputtering parameters for InAs/GaSb films.
• Analysis of film structure, morphology, and crystallization.
• Fabrication and characterization of InAs/GaSb PDs at room temperature.

Main Results:

• Elevated temperatures caused Sb diffusion and stratification; rapid thermal annealing suppressed diffusion but induced island growth.
• Substrate-induced crystallization via controlled sputtering time yielded highly crystalline, smooth GaSb films.
• InAs films on optimized GaSb buffer layers showed enlarged grain size, reducing recombination centers.
• Fabricated InAs/GaSb PDs achieved a dark current density of 1.1 × 10^-3 A/cm².
• Room-temperature responsivity reached 1.32 A/W (1310 nm) and 3.46 A/W (1550 nm).
• Specific detectivity reached 7.04 × 10¹⁰ Jones (1310 nm) and 1.84 × 10¹¹ Jones (1550 nm).

Conclusions:

• Magnetron sputtering is a viable method for fabricating high-quality InAs/GaSb films.
• Optimized growth parameters, particularly substrate-induced crystallization, are key to suppressing defects and enhancing performance.
• This approach offers a promising route for cost-effective, high-performance III-V heterojunction photodetectors.