Ultrathin Ag films on H:Si(111)-1×1 surfaces deposited at low temperatures

Abstract

The growth, structure, and electronic properties of thin Ag films on H-terminated Si(111) surfaces were investigated with Auger electron and photoelectron spectroscopy (and atomic force and secondary electron microscopy). The films were either evaporated at room temperature (RT) or deposited at low temperature (LT) and subsequently annealed to RT in the thickness range between 1 and 50 monolayers (0.2–12 nm). The LT preparation leads to large Ag islands on a wetting monolayer which form a continuous Ag film above a critical thickness of 30 monolayers. Ultraviolet photoelectron spectra and work function measurements reveal a (111) surface orientation of the Ag islands. In constrast, RT deposition results in Stranski-Krastanov growth of smaller and irregularly shaped islands which do not form a continuous layer even up to film thicknesses of 45 monolayers.