ADSORPTION OF O-ADATOMS ON HYDROGENATED SI CLUSTER

The adsorption of an O adatom on the most stable hydrogenated Si clust er (Si6H12) has been explored for the first time by using first princi ples. Two interesting adsorption configurations are found: In the firs t one, a striking feature is the substitutional adsorption: the O adat om forms a bond with a Si atom in the substrate cluster, which release s a H atom, and the H atom is in turn bonded to the adatom, exhibiting a similar feature to the Si adatom on the hydrogenated Si(100) surfac e. In the second one, the O adatom breaks the Si-Si bond and is bridge -bonded to two Si atoms, which not only exhibits the key structural fe ature for Si oxide clusters with ring and chain structure, but also di splays the characteristics of oxidation of the Si(001) surface and oxy gen impurities in bulk silicon. The latter structure is more stable th an the former.