Photodesorption and Photofragmentation of Disilane Adsorbed on a Hydrogen Terminated Si(100) Surface
In: Surface Science, Jg. 390 (1997) ; Nr. 1-3, pp. 209 - 213
Zeitschriftenaufsatz / Fach: Chemie
The photochemical mechanisms leading to the desorption and fragmentation of Si₆H₆ adsorbed on a hydrogen terminated Si(100) surface have been explored by recording the time-of-flight distributions of products escaping from the surface and by using electron energy loss spectroscopy to probe possible electronic excitations. Photodesorption of intact Si(sub 2)H₆ involves hot electrons that lose energy and move to the conduction band edge before initiating desorption. When the wavelength of the incident light is 193 nm, Si₂H₆ fragments give mostly Si, SiH₂, H₂ and SiH₄, but this pathway is quenched at longer wavelengths. This is consistent with direct excitation, but we also show that a negative ion resonance is accessible to substrate electrons that have been excited by 193 nm light.