Unprecedented Piezoresistance Coefficient in Strained Silicon Carbide

Area of Science:

• Materials Science
• Nanotechnology
• Solid-State Physics

Background:

• Piezoresistance coefficients of silicon carbide (SiC) nanowires (NWs) are reported to be smaller than bulk counterparts.
• Contamination during NW adhesion to substrates presents a significant challenge for accurate measurements.

Purpose of the Study:

• To develop a novel setup for manipulating and fixing SiC NWs without deposition-based contamination.
• To perform in situ electromechanical coupling measurements on pristine SiC NWs using transmission electron microscopy (TEM).

Main Methods:

• A new manipulation technique using goat hair and conductive silver epoxy in air was employed.
• In situ TEM was utilized for electromechanical coupling measurements.
• The goat hair's stiffness and tapered tip facilitated manipulation without material loss.

Main Results:

• The piezoresistance coefficient and carrier mobility of SiC NWs were measured to be -94.78 × 10^-11 Pa^-1 and 30.05 cm² V^-1 s^-1, respectively.
• These values are significantly higher (82 and 527 times) than previously reported for SiC NWs.
• For the first time, the piezoresistance coefficient of SiC NWs was found to be 17 times greater than their bulk counterparts.

Conclusions:

• The developed method enables accurate in situ measurements of SiC NW properties.
• The study reveals significantly enhanced piezoresistance in SiC NWs compared to bulk SiC.
• Findings offer potential for developing high-performance SiC devices for harsh environments.