Growth of Si on Si(111)-7 x 7 at room temperature under laser substrate excitation

The effect of laser substrate excitation on homoepitaxy of Si(111)-7 x 7 growth by femtosecond pulsed laser deposition is studied using reflection high-energy electron diffraction (RHEED). Laser excitation of the substrate with energy density significantly below its surface damage threshold results in a drastic change in the growth mode leading to epitaxial growth at room temperature. The morphology changes from rough surface with formation of clusters with different sizes for growth without laser excitation to oriented triangular-shaped islands with excitation. A nonthermal mechanism is responsible for the change in growth morphology with laser excitation increasing the adatom surface diffusion coefficient.