GROWTH OF GASE ULTRATHIN FILMS ON SI(111) SUBSTRATES ANALYZED BY THE X-RAY STANDING-WAVE TECHNIQUE

The epitaxial growth of very thin GaSe films on H-Si(111), 7 x 7-Si(11 1), and root 3 x root 3 Ga-Si(111) has been investigated using the x-r ay standing-wave technique. The interface structure was found to be id entical whatever the Si(111) surface preparation used and consists of a GaSe half-layer. Ga atoms are covalently bonded with Si top atoms an d are located in T sites. Beyond the interface, the growth proceeds la yer by layer and not atomic plane by atomic plane. Moreover, the first complete layer above the interface is almost completely relaxed with respect to the Si substrate.