A spin-polarized density functional theory calculation was carried out to characterize the adsorption and decomposition of Si2H5 radical on the clean and H-covered Si(100)-(2 × 1) surface. The adsorption structures and energies of Si2H5, Si2H 4, SiH3, and SiH2 on the Si(100)-(2 × 1) surface were predicted. It was found that Si2H5, Si 2H4, SiH3, and SiH2 preferentially adsorb at the dimer-a, intrarow, dimer-b, and in-dimer sites, respectively. Potential energy profiles for the reactions of Si2H5 radical on the clean and H-covered Si(100)-(2 × 1) surfaces were constructed using the nudged elastic band (NEB) method. Calculations show that the Si2H5 radical can easily decompose to Si 2H4(a), SiH3(a), SiH2(a), and H (a) without any thermal activation, and the decomposition of Si(100)/Si2H5(a) → Si2H 4(a)/Si(100)/H(a) may be the dominant mechanism on the clean Si(100) surface because of its low barrier and high exothermicity. The most likely mechanism for the reaction of Si2H5 on the H-covered Si(100)-(2 × 1) surface is the reaction of Si2H 5(a) + H(a) → 2SiH3(a) with an exothermicity of 2.3 kcal/mol by passing a barrier of 59.9 kcal/mol.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films