Abstract
We report measurements of excited-state lifetimes for Si-H stretching vibrational modes of steps and terraces on chemically prepared, hydrogen-terminated vicinal Si(111) surfaces using picosecond pump-probe surface spectroscopy. The steps present on these vicinal surfaces are shown to play an important role in the vibrational energy relaxation pathways. Three types of vicinal Si(111) surfaces are studied, all having monohydride-terminated terraces but differing in step termination or in step density. Two surfaces are cut along the (112) direction, 9° and 5° from the (111) plane, respectively. Both of these surfaces have dihydride-terminated steps. A third surface is cut 9° from the (111) plane along the (112) direction and has monohydride-terminated steps. Two normal modes of the dihydride-terminated steps show vibrational energy relaxation times of ∼100 ps [≤80 ps and 130(20) ps, uncertainty in parentheses], while the monohydride-terminated steps relax 10 times more slowly with an 1100(120) ps lifetime. On the dihydride-stepped 9° surface the lifetime of the terrace mode is shortened to 420(40) ps from the flat surface lifetime of 950(100) ps, while on the monohydride-stepped surface the terrace mode lifetime is 820(80) ps. The results are explained by energy transfer between the terrace and the step Si-H modes. The different dynamics on the monohydride-and dihydride-stepped surfaces arise because the short-lifetime dihydride steps act as energy drains, while the long-lifetime monohydride steps do not. Dipole-dipole coupling between the Si-H stretching modes can account for the interadsorbate vibrational energy transfer observed.
| Original language | English |
|---|---|
| Pages (from-to) | 6203-6212 |
| Number of pages | 10 |
| Journal | Journal of Chemical Physics |
| Volume | 96 |
| Issue number | 8 |
| Publication status | Published - 1992 |
Fingerprint
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
Cite this
Vibrational energy transfer on hydrogen-terminated vicinal Si(111) surfaces : Interadsorbate energy flow. / Morin, M.; Jakob, P.; Levinos, N. J.; Chabal, Y. J.; Harris, Alex.
In: Journal of Chemical Physics, Vol. 96, No. 8, 1992, p. 6203-6212.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Vibrational energy transfer on hydrogen-terminated vicinal Si(111) surfaces
T2 - Interadsorbate energy flow
AU - Morin, M.
AU - Jakob, P.
AU - Levinos, N. J.
AU - Chabal, Y. J.
AU - Harris, Alex
PY - 1992
Y1 - 1992
N2 - We report measurements of excited-state lifetimes for Si-H stretching vibrational modes of steps and terraces on chemically prepared, hydrogen-terminated vicinal Si(111) surfaces using picosecond pump-probe surface spectroscopy. The steps present on these vicinal surfaces are shown to play an important role in the vibrational energy relaxation pathways. Three types of vicinal Si(111) surfaces are studied, all having monohydride-terminated terraces but differing in step termination or in step density. Two surfaces are cut along the (112) direction, 9° and 5° from the (111) plane, respectively. Both of these surfaces have dihydride-terminated steps. A third surface is cut 9° from the (111) plane along the (112) direction and has monohydride-terminated steps. Two normal modes of the dihydride-terminated steps show vibrational energy relaxation times of ∼100 ps [≤80 ps and 130(20) ps, uncertainty in parentheses], while the monohydride-terminated steps relax 10 times more slowly with an 1100(120) ps lifetime. On the dihydride-stepped 9° surface the lifetime of the terrace mode is shortened to 420(40) ps from the flat surface lifetime of 950(100) ps, while on the monohydride-stepped surface the terrace mode lifetime is 820(80) ps. The results are explained by energy transfer between the terrace and the step Si-H modes. The different dynamics on the monohydride-and dihydride-stepped surfaces arise because the short-lifetime dihydride steps act as energy drains, while the long-lifetime monohydride steps do not. Dipole-dipole coupling between the Si-H stretching modes can account for the interadsorbate vibrational energy transfer observed.
AB - We report measurements of excited-state lifetimes for Si-H stretching vibrational modes of steps and terraces on chemically prepared, hydrogen-terminated vicinal Si(111) surfaces using picosecond pump-probe surface spectroscopy. The steps present on these vicinal surfaces are shown to play an important role in the vibrational energy relaxation pathways. Three types of vicinal Si(111) surfaces are studied, all having monohydride-terminated terraces but differing in step termination or in step density. Two surfaces are cut along the (112) direction, 9° and 5° from the (111) plane, respectively. Both of these surfaces have dihydride-terminated steps. A third surface is cut 9° from the (111) plane along the (112) direction and has monohydride-terminated steps. Two normal modes of the dihydride-terminated steps show vibrational energy relaxation times of ∼100 ps [≤80 ps and 130(20) ps, uncertainty in parentheses], while the monohydride-terminated steps relax 10 times more slowly with an 1100(120) ps lifetime. On the dihydride-stepped 9° surface the lifetime of the terrace mode is shortened to 420(40) ps from the flat surface lifetime of 950(100) ps, while on the monohydride-stepped surface the terrace mode lifetime is 820(80) ps. The results are explained by energy transfer between the terrace and the step Si-H modes. The different dynamics on the monohydride-and dihydride-stepped surfaces arise because the short-lifetime dihydride steps act as energy drains, while the long-lifetime monohydride steps do not. Dipole-dipole coupling between the Si-H stretching modes can account for the interadsorbate vibrational energy transfer observed.
UR - http://www.scopus.com/inward/record.url?scp=0000034333&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0000034333&partnerID=8YFLogxK
M3 - Article
VL - 96
SP - 6203
EP - 6212
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
SN - 0021-9606
IS - 8
ER -