Morphology and structure of Pb thin films grown on Si(111) by pulsed laser deposition

Thin Pb films were grown by pulsed laser deposition on Si(111) at various laser fluences, pulse wavelengths, deposition time, and substrate temperatures. Scanning electron microscopy and ex situ atomic force microscopy were used to probe the surface morphology and structure. At room temperature, increasing the laser fluence and/or the pulse wavelength triggers the transformation from the “worm”-like interconnected islands to granular, separated islands. Increasing the substrate temperature to slightly below the Pb melting temperature results in the formation of large, nearly spherical non-wetting islands. Additionally, ultrathin Pb (111) films were grown at room temperature, which resulted in a small number of nearly 2D islands due to the emerging quantum size effect. Our results show that pulsed laser deposition can be used effectively for controlled growth of Pb thin films.