Superhard silicon nanospheres

Successful deposition and mechanical probing of nearly spherical, defect-free silicon nanospheres has been accomplished. The results show silicon at this length scale to be up to four times harder than bulk silicon. Detailed measurements of plasticity evolution and the corresponding hardening response in normally brittle silicon is possible in these small volumes. Based upon a proposed length scale related to the size of nanospheres in the 20-50 nm radii range, a prediction of observed hardnesses in the range of 20-50 GPa is made. The ramifications of this to computational materials science studies on identical volumes are discussed. © 2003 Elsevier Science Ltd. All rights reserved.