کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5426129 | 1395877 | 2007 | 7 صفحه PDF | دانلود رایگان |
We have studied the direct and indirect abstraction of D adatoms by H on the Si(1 0 0) surfaces by employing a pulsed H-beam. Desorptions of HD molecules is found to occur promptly as a result of direct abstraction at the beam on-cycles. In contrast, we find that D2 desorption induced by adsorption of H atoms, i.e., the so-called adsorption-induced desorption (AID), occurs even at the beam off-cycles. The D2 rate curves measured with the pulsed-H beam are decomposed into four components characterized with the reaction lifetimes of ⩽0.005, 0.06 ± 0.01, 0.8 ± 0.1, and 30 ± 5 s. We propose that the fastest and the second fastest AID channels are related to the thermodynamical instability of (1 Ã 1) dihydride domains locally formed on the (3 Ã 1) monodeuteride/dideuteride domains. The 0.8 s AID channel is attributed to the desorption occurring at the stage when (3 Ã 1) monodeuteride/dideuteride domains are built up upon H adsorption onto the (2 Ã 1) monohydride surface. The 30 s AID path is attributed to the thermal desorption accompanied by the shrinkage of the (3 Ã 1) domains which were excessively formed during the beam on-cycles on the (2 Ã 1) monohydride surface. Atomistic mechanisms are proposed for these three AID pathways.
Journal: Surface Science - Volume 601, Issue 6, 15 March 2007, Pages 1635-1641