Pb layer-by-layer growth at very low temperatures.

Abstract

We have studied the growth of ultrathin Pb films on Si(111)-(6\ifmmode\times\else\texttimes\fi{}6)Au surfaces at very low temperatures by reflection high-energy electron diffraction (RHEED) and resistivity measurements. Pronounced RHEED specular beam intensity oscillations were recorded at temperatures as low as 16 K. The domain size on the surface of the growing Pb film was determined from the width of RHEED streaks. The electrical resistivity data were analyzed using the quantum size effect theory of Trivedi and Ashcroft. The mean free path of the Pb conduction electrons was determined and compared with the size of the Pb surface domains and with the size of the (6\ifmmode\times\else\texttimes\fi{}6) Au substrate domains. The role of morphology and electronic structure of the Si(111)-(6\ifmmode\times\else\texttimes\fi{}6)Au surface and of transient mobility during the nucleation of the growing Pb film is discussed.