Effect of electronic strain on the optically induced mechanical moment in silicon microstructures

A model for the effect of the presence of photogenerated electron-hole pairs on the optically induced mechanical moment in a silicon cantilever beam has been developed. This effect is twofold and is the consequence of electronic strain on one hand and of the recombination heat of the photogenerated electron-hole pairs on the other. It manifests itself by a deviant phase- frequency relation of the vibrating beam in comparison with a pure thermally excited beam. Experiments have been performed, and the results show excellent agreement with the model.