Desorption from Si (100)
نویسنده
چکیده
Ab initio molecular dynamics calculations of deuterium desorbing from Si(100) have been performed in order to monitor the energy redistribution among the hydrogen and silicon degrees of freedom during the desorption process. The calculations show that part of the potential energy at the transition state to desorption is transferred to the silicon lattice. The deuterium molecules leave the surface vibrationally hot and rotationally cold, in agreement with experiments; the mean kinetic energy, however, is larger than found in experiments.
منابع مشابه
A dynamically and kinetically consistent mechanism for H2 adsorption/desorption from Si(100)-2 x 1.
Curiously, H2 desorption from Si~100!-231 follows approximately first-order kinetics rather than the expected second-order kinetics, arousing interest about the mechanism involved in the desorption process. We investigate the energetics and rate constants of three proposed mechanisms for H2 desorption from Si~100!231, namely, the prepairing mechanism, the isomerization mechanism, and the isolat...
متن کاملDesorption dynamics of deuterium molecules from the Si(100)-(3x1) dideuteride surface.
We measured polar angle (theta)-resolved time-of-flight spectra of D2 molecules desorbing from the Si(100)-(3x1) dideuteride surface. The desorbing D2 molecules exhibit a considerable translational heating with mean desorption kinetic energies of approximately 0.25 eV, which is mostly independent of the desorption angles for 0 degrees<or=theta<or=30 degrees. The observed desorption dynamics of ...
متن کاملAtomistic view of the recombinative desorption of H2 from H/Si(100).
Scanning tunneling microscopy is employed to investigate the recombinative desorption of H2 from hydrogenated Si(100) surfaces consisting of dihydride (SiH2) and monohydride (SiH) surface species organized in (1 x 1), (3 x 1), and (2 x 1) configurations. The results show that desorption from dihydrides involves a pair of neighboring dihydrides linked along the tetrahedral bond direction. Dihydr...
متن کاملCalculation of desorption and migration of hydrogen on SiGe(100)-2×1 surface using density functional theory
Ab initio calculations have been carried out to investigate the H-atom migration and H2 desorption on the mixed SiGe(100)-2×1 surface using the Si9-xGexH13, Si14GeH19 and Si13Ge2H19 cluster models. The H2 recombinative desorption is the rate-determining step in hydrogen migration and desorption on SiGe(100) surface since the energy barrier of H-atom migration is generally lower than that of H2 ...
متن کاملv 3 2 9 M ar 1 99 5 A direct pathway for sticking / desorption of H 2 on Si ( 100 )
The energetics of H2 interacting with the Si(100) surface is studied by means of ab initio total energy calculations within the framework of density functional theory. We find a direct desorption pathway from the mono-hydride phase which is compatible with experimental activation energies and demonstrate the importance of substrate relaxation for this process. Both the transition state configur...
متن کامل