Femtosecond pulsed laser deposition of Ge quantum dot growth on Si(1 0 0)-(2 x 1)

Ge quantum dots were grown on Si(1 0 0)-(2 x 1) by femtosecond pulsed laser deposition at various substrate temperatures using a femtosecond Ti:sapphire laser. In situ reflection high-energy electron diffraction and ex situ atomic force microscopy were used to analyze the film structure and morphology. The morphology of germanium islands on silicon was studied at different coverages. The results show that femtosecond pulsed laser deposition reduces the minimum temperature for epitaxial growth of Ge quantum dots to ∼280 deg. C, which is 120 deg. C lower than previously observed in nanosecond pulsed laser deposition and more than 200 deg. C lower than that reported for molecular beam epitaxy and chemical vapor deposition.