Plasmon Excitations in Thin Alkali Metal Films on Si(111)7 × 7

✍ Scribed by Pedersen, K. ;Hansen, P.-E. ;Morgen, P.

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 153 KB
• Volume: 170
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/(sici)1521-396x(199812)170:2<411::aid-pssa411>3.0.co;2-e

✦ Synopsis

The growth of thin Cs and K films on Si(111)7 Â 7 kept at 170 K has been followed by second harmonic generation (SHG) during continuous deposition. Initially, both types of alkali atoms adsorb at dangling bond sites, in a similar way as at room temperature. At low temperature the completion of one overlayer is followed by multilayer growth. This causes orders of magnitude increase of SHG due to excitations of plasmons. A fairly sharp transition temperature below which multilayers can exist was found at 260 K for both metals. For Cs the variations in SHG with exposure can be explained in terms of coverage variations of the resonance frequency. The variations of SHG during deposition of K indicate the formation of islands.