摘要
The geometric, electronic, and photoabsorption properties of some hydrogenated silicon clusters are investigated. The density functional theory with generalized gradient approximation fimctional is applied. Our study shows that the geometric structures of them relax with their increasing sizes. Synchronously, the polarizations of Si-H bonds become weak slowly but overlap populations increase. In Mulliken population analysis, we find a distinctive passivation effect （some electrons are transferred from outer Si atoms to the central Si with four-coordinate Si atoms）. Owing to the quantum confinement, the energy gap and the lowest excitation energy increase with the decreasing sizes. For nanometer scale cluster, the transition from the highest occupied molecular orbital to the lowest unoccupied molecular orbital state is usually prohibited.
The geometric, electronic, and photoabsorption properties of some hydrogenated silicon clusters are investigated. The density functional theory with generalized gradient approximation fimctional is applied. Our study shows that the geometric structures of them relax with their increasing sizes. Synchronously, the polarizations of Si-H bonds become weak slowly but overlap populations increase. In Mulliken population analysis, we find a distinctive passivation effect （some electrons are transferred from outer Si atoms to the central Si with four-coordinate Si atoms）. Owing to the quantum confinement, the energy gap and the lowest excitation energy increase with the decreasing sizes. For nanometer scale cluster, the transition from the highest occupied molecular orbital to the lowest unoccupied molecular orbital state is usually prohibited.
基金
supported by the Hebei North University Foundation (No.200706)
