Abstract
Two hand-built continuous random network structural models of the transition region between an Si(111) surface and an amorphous SiO2 overlayer have been constructed. The models contain 354 and 329 atoms, respectively and differ in the degree of disorder. The transition region contains at least three atomic layers of SiOx (02 and a relatively high deformation energy. The SiO2 overlayer is probably fully disordered. The models were relaxed with respect to Keating and Coulomb forces; the latter led, however, only to minor changes of the structure. The bond angles at oxygen atoms have an average value of 144′ with an r.m.s. deviation of about 10°. The statistics of the Si(Si4-nOn) tetrahedra corresponds to the random-bonding model.