Determination of Young’s modulus of carbon nanofiber probes fabricated by the argon ion bombardment of carbon coated silicon cantilever

Abstract

A single amorphous carbon nanofiber (CNF) was grown on a commercial Si cantilever by the argon ion (Ar +) bombardment of carbon coated silicon cantilever. The CNF probe was mounted on a piezo controlled arm opposing a soft cantilever to measure the axial force acting on the CNF in a scanning electron microscope (SEM). The buckling force was measured while observing the buckling behavior. The CNF probes have an elliptical cross section with short and long axis of 20–29 and 25–59 nm, respectively, and a length of 350–760 nm. The Young’s modulus was determined from Euler’s formula using the measured buckling force and had a value of 38–48 GPa, almost independent of the CNF size. The Young’s modulus was lower than that of high quality carbon nanotubes (CNTs) and higher than that of defective CNTs. It was also demonstrated that the CNF probes were elastic, similar to the CNT probes. Thus CNF probes produced by Ar + ion bombardment are quite promising as practical nanocarbon probes.