Photon-Triggered Current Generation in Chemically-Synthesized Silicon Nanowires

Area of Science:

• Nanotechnology
• Materials Science
• Optoelectronics

Background:

• Porous silicon segments in silicon nanowires (Si NWs) exhibit light-triggered current generation with high on/off ratios.
• This property has been leveraged for photon-triggered NW devices like transistors, logic gates, and photodetectors.

Purpose of the Study:

• To develop a reliable and simple fabrication procedure for porous Si segments in chemically synthesized Si NWs.
• To enable photon-triggered current generation for advanced electronic and photonic applications.

Main Methods:

• Utilized 100 nm-diameter, n-type, high-doping Si NWs grown by chemical vapor deposition.
• Employed metal-assisted chemical etching with silver nanoparticles to selectively create porous Si regions.
• Fabricated contact electrodes and measured current generation under laser illumination.

Main Results:

• Achieved high on/off ratios up to 1.5 × 10^4 at a 5 V forward bias.
• Demonstrated tunable current by controlling laser power and bias voltage.
• Observed decreased responsivity for porous segment lengths exceeding 360 nm.
• Fabricated a single Si NW with nine porous segments functioning as a high-resolution photodetector.

Conclusions:

• The developed fabrication method allows precise control over porous Si segment position and length.
• This precise control opens possibilities for practical implementation of programmable logic gates.
• The method facilitates the development of ultrasensitive photodetectors and advanced NW devices.