Au-In Alloy for Excellent Ohmic Contact in GeSe Devices with Enhanced Photodetector Properties

Area of Science:

• Materials Science
• Semiconductor Physics
• Nanotechnology

Background:

• Metal-semiconductor contacts are crucial for electronic and optoelectronic devices.
• Achieving low contact resistance is essential for device performance.

Purpose of the Study:

• To investigate the performance of Au-In alloy contacts in Germanium Selenide (GeSe) devices.
• To understand the mechanism behind the low contact resistance and its impact on device characteristics.

Main Methods:

• Experimental measurement of contact resistance (R_C) in GeSe-Au-In devices.
• Density Functional Theory (DFT) calculations to analyze interface properties.
• Fabrication and characterization of GeSe-Au-In photodetectors.

Main Results:

• Achieved a state-of-the-art low R_C of 25 kΩ μm in GeSe-Au-In devices.
• Identified a small barrier height of 16 meV contributing to low R_C.
• DFT revealed a highly conductive metallic interface due to indium doping, mitigating interface states.
• GeSe-Au-In photodetectors demonstrated enhanced photoresponsivity (6.46 × 10⁴ A/W) and detectivity (8.9 × 10¹³ Jones).

Conclusions:

• Au-In alloy contact is highly effective for low-resistance interfaces in GeSe devices.
• Indium doping plays a key role in forming a conductive metallic interface.
• The developed GeSe-Au-In devices show potential for high-performance optoelectronic applications.