  We studied the low temperature (T<130K) growth of Ag on Si(001) and Si(111)
flat surfaces prepared by Si homo epitaxy with the aim to achieve thin metallic
films. The band structure and morphology of the Ag overlayers have been
investigated by means of XPS, UPS, LEED, STM and STS. Surprisingly a
(root3xroot3)R30^o LEED structure for Ag films has been observed after
deposition of 2-6 ML Ag onto a Si(111)(root3xroot3)R30^o Ag surface at low
temperatures. XPS investigations showed that these films are solid, and UPS
measurements indicate that they are metallic. However, after closer STM studies
we found that these films consists of sharp Ag islands and (root3xroot3)R30^o
Ag flat terraces in between. On Si(001) the low-temperature deposition yields
an epitaxial growth of Ag on clean Si(001)2x1 with a twinned Ag(111) structure
at coverages as low as 10 ML. Furthermore the conductivity of few monolayer Ag
films on Si(100) surfaces has been studied as a function of temperature (40-300
K).
