Sensitive Metal-Semiconductor Nanothermocouple Fabricated by FIB to Investigate Laser Beams with Nanometer Spatial...

Area of Science:

• Materials Science
• Nanotechnology
• Physics

Background:

• Traditional nanothermocouple fabrication requires specialized semiconductor manufacturing facilities.
• Focused Ion Beam (FIB) systems offer a more accessible fabrication route for nanodevices.
• Metal-semiconductor nanothermocouples present an alternative to metal-metal structures.

Purpose of the Study:

• To fabricate a novel metal-semiconductor nanothermocouple using FIB.
• To evaluate the sensitivity and response of the nanothermocouple to thermal stimuli.
• To explore the potential applications of FIB-fabricated nanothermocouples in laser beam characterization.

Main Methods:

• Fabrication of a platinum-silicon (Pt-Si) nanothermocouple with a 90 nm nanojunction using Focused Ion Beam (FIB).
• Characterization of the nanothermocouple's response to a stream of hot air for temperature sensing.
• Analysis of the nanothermocouple's nonlinear response to an argon-laser beam with high optical power density.
• Laser annealing of metal-semiconductor interfaces using the argon laser.

Main Results:

• The Pt-Si nanothermocouple exhibited a Seebeck coefficient up to 140 µV/K, showing 10 times higher sensitivity than typical metal-metal nanothermocouples.
• A linear response was observed for temperature measurements using hot air, enabling sensitive detection of small temperature changes.
• A nonlinear response up to 83.85 mV was recorded under high-power argon laser irradiation.
• The FIB fabrication process is accessible in standard research labs and can be performed quickly by a single operator.

Conclusions:

• FIB is a viable and accessible technique for fabricating high-sensitivity metal-semiconductor nanothermocouples.
• These nanothermocouples demonstrate potential for accurate temperature measurements and laser beam characterization at the nanoscale.
• Further improvements in FIB processing, such as using different metal sources, could enhance the Seebeck coefficient even more.