### Abstract

Molecular dynamics simulation for hydrogen-covered Si(1 0 0):H-2 × 1 silicon surface was carried out to calculate the vibrational energy relaxation rates of Si-H stretches based on the Bloch-Redfield theory. The calculation gave a lifetime of 0.35 ns at 300 K, about three times shorter than the experimental result of 1.2 ns. With a reduction of force constants for the first layer reconstructed silicon dimer Si-Si stretches and Si-Si-Si bends by multiplying with 0.9 in this molecular mechanics force field, the calculation gave a lifetime of 0.51 ns, closer to the experimental result than the calculated result above. This suggests that the vibrational frequencies of first layer silicon dimers should be lower than the bulk modes. In addition, it is noted that the Si-Si-H bending frequency of 625 cm^{-1} on this Si(1 0 0):H-2 × 1 surface is lower than the 640 cm^{-1} on the Si(1 1 1):H-1 × 1 surface but the lifetime of Si-H stretches on (1 0 0) surface is shorter than (1 1 1) surface. This is in contrast to a result in a previous study for (1 1 1) surface in which the higher Si-Si-H bending frequency should result in a shorter lifetime. These results indicate that the couplings between Si-H stretches and Si-Si-H bends on the Si(1 0 0):H-2 × 1 surface differ significantly from the Si(1 1 1):H-1 × 1 surface. Besides discussion of this coupling, the isotope and thermal effects in the calculated lifetimes are reported and discussed as well.

Original language | English |
---|---|

Pages (from-to) | L540-L546 |

Journal | Surface Science |

Volume | 516 |

Issue number | 3 |

DOIs | |

Publication status | Published - 2002 Sep 20 |

### Fingerprint

### Keywords

- Computer simulations
- Molecular dynamics
- Semiconducting surfaces
- Silicon
- Vibrations of adsorbed molecules

### ASJC Scopus subject areas

- Condensed Matter Physics
- Surfaces and Interfaces
- Surfaces, Coatings and Films
- Materials Chemistry

### Cite this

**Molecular dynamics simulation of hydrogen-covered reconstructed Si(1 0 0):H-2 × 1 silicon surface : Calculation of vibrational energy relaxation rates of hydrogen stretching modes.** / Ho, Ming Hsun; Sun, Ying Chieh.

Research output: Contribution to journal › Article

}

TY - JOUR

T1 - Molecular dynamics simulation of hydrogen-covered reconstructed Si(1 0 0):H-2 × 1 silicon surface

T2 - Calculation of vibrational energy relaxation rates of hydrogen stretching modes

AU - Ho, Ming Hsun

AU - Sun, Ying Chieh

PY - 2002/9/20

Y1 - 2002/9/20

N2 - Molecular dynamics simulation for hydrogen-covered Si(1 0 0):H-2 × 1 silicon surface was carried out to calculate the vibrational energy relaxation rates of Si-H stretches based on the Bloch-Redfield theory. The calculation gave a lifetime of 0.35 ns at 300 K, about three times shorter than the experimental result of 1.2 ns. With a reduction of force constants for the first layer reconstructed silicon dimer Si-Si stretches and Si-Si-Si bends by multiplying with 0.9 in this molecular mechanics force field, the calculation gave a lifetime of 0.51 ns, closer to the experimental result than the calculated result above. This suggests that the vibrational frequencies of first layer silicon dimers should be lower than the bulk modes. In addition, it is noted that the Si-Si-H bending frequency of 625 cm-1 on this Si(1 0 0):H-2 × 1 surface is lower than the 640 cm-1 on the Si(1 1 1):H-1 × 1 surface but the lifetime of Si-H stretches on (1 0 0) surface is shorter than (1 1 1) surface. This is in contrast to a result in a previous study for (1 1 1) surface in which the higher Si-Si-H bending frequency should result in a shorter lifetime. These results indicate that the couplings between Si-H stretches and Si-Si-H bends on the Si(1 0 0):H-2 × 1 surface differ significantly from the Si(1 1 1):H-1 × 1 surface. Besides discussion of this coupling, the isotope and thermal effects in the calculated lifetimes are reported and discussed as well.

AB - Molecular dynamics simulation for hydrogen-covered Si(1 0 0):H-2 × 1 silicon surface was carried out to calculate the vibrational energy relaxation rates of Si-H stretches based on the Bloch-Redfield theory. The calculation gave a lifetime of 0.35 ns at 300 K, about three times shorter than the experimental result of 1.2 ns. With a reduction of force constants for the first layer reconstructed silicon dimer Si-Si stretches and Si-Si-Si bends by multiplying with 0.9 in this molecular mechanics force field, the calculation gave a lifetime of 0.51 ns, closer to the experimental result than the calculated result above. This suggests that the vibrational frequencies of first layer silicon dimers should be lower than the bulk modes. In addition, it is noted that the Si-Si-H bending frequency of 625 cm-1 on this Si(1 0 0):H-2 × 1 surface is lower than the 640 cm-1 on the Si(1 1 1):H-1 × 1 surface but the lifetime of Si-H stretches on (1 0 0) surface is shorter than (1 1 1) surface. This is in contrast to a result in a previous study for (1 1 1) surface in which the higher Si-Si-H bending frequency should result in a shorter lifetime. These results indicate that the couplings between Si-H stretches and Si-Si-H bends on the Si(1 0 0):H-2 × 1 surface differ significantly from the Si(1 1 1):H-1 × 1 surface. Besides discussion of this coupling, the isotope and thermal effects in the calculated lifetimes are reported and discussed as well.

KW - Computer simulations

KW - Molecular dynamics

KW - Semiconducting surfaces

KW - Silicon

KW - Vibrations of adsorbed molecules

UR - http://www.scopus.com/inward/record.url?scp=0037144341&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0037144341&partnerID=8YFLogxK

U2 - 10.1016/S0039-6028(02)02023-X

DO - 10.1016/S0039-6028(02)02023-X

M3 - Article

AN - SCOPUS:0037144341

VL - 516

SP - L540-L546

JO - Surface Science

JF - Surface Science

SN - 0039-6028

IS - 3

ER -