Geometric structure of the Si(111)√3×√3-Ga surface

Abstract

The structure of the Si(111}&3&&3-Gasurface has been studied by dynamic analysis of lowenergy electron-diffraction curves of intensity versus energy (I-V). It has been found that a structure in which Ga atoms are located on the second layer of Si atoms well explains the experimentally obtained I-V curves. In this geometry, a large deformation of the surface layer results from the stable adsorption of Ga atoms. The optimum configuration is close to that proposed by Northrup in his study of the Si(111}&3 & &3-Al surface.Among the reconstructed surface structures which are formed on the (111) surface of crystals with fcc or diamond structures, the~3 X &3 structure is the most frequently observed, and many experimental and theoretical studies related to it have already been published. ' However, in only a few cases has the geometry of the surface been successfully determined. In most cases, this is mainly due to inadequate use of the methods of measurement. In the case of low-energy electron-difFraction (LEED) studies, sufficient data to determine the surface geometry can be obtained by measuring the intensityenergy (I-V) curves of diffracted beams. Shortcomings of LEED analyses include the necessity of complicated calculations and the considerable computing time required to perform this kind of calculation. ' However, recent advances in computer technology enable us to study reconstructed surface structures whose surface unit cells contain fairly large numbers of atoms.In this study we report the results of dynamic analysis of the I-V curves of LEED from the Si(111)&3Xv 3-Ga surface.We used n-type silicon wafers of high resistivity ( & 10 kQcm), cut to within 1' parallel to the (111) plane, as substrates. A molecular beam of Ga from a Knudsen cell was impinged on the silicon surface. The saturation coverage of Ga atoms for the +3X +3 structure has been determined as -, ' of a monolayer by quadrupole mass spectroscope observation of the increase in intensity of the desorption Aux of Ga atoms from the Si surface after the completion of the &3 X &3 phase at high substrate temperatures, and by observing the break points in curves of Auger-electron-spectroscopy signal versus deposition time. ' %'hen -, ' of a monolayer of Ga atoms was deposited at 740 K, an unambiguous Si(111)/3 X &3 structure was observed. I-V curves from the Si(ill)v 3Xv 3 surface have been obtained by measuring the brightness of the bright spots on the Auorescent screen by means of a spot photometer. The calculations of I-V curves were performed using a renormalized forward-scattering algorithm. The scattering matrices for nonequivalent composite layers were calculated by a matrix inversion formalism, and the intensity of the beams rejected from a stack of these composite layers 0 0 0 0 0 o Ga FIG. 1. Top and side views of the surface structural model. was obtained by the renormalized forward scattering perturbation method. The computer programs developed by Pendry and by Tong and van Hove were modi6ed to apply to cases in which the substrate layers c...

Growth process and morphology of three‐dimensional GaSb islands on Ga/Si(111)

“…The first bi-atomic GaSb layer grown on Ga/Si(111)-√3×√3 covered the entire surface [15]. With increasing coverage of GaSb at 300 °C, dome-shaped islands abruptly formed on the third GaSb layer grown on the local surface area [16]. However, dome-shaped islands were not observed at 350 °C, and the faceted islands from multilayer growth were evenly formed.…”

“…The Ga/Si(111)-√3×√3 was formed by the deposition of 0.3 ML Ga on a clean Si(111) surface at 550 °C ( Fig. 1(b)) [16]. GaSb was grown by the simultaneous deposition of Ga and Sb atoms at 300-450 °C.…”

The physics and chemistry of the Schottky barrier height

“…, Si(111)6.3 Â 6.3-Ga, [424][425][426][427] Si(111) 1 Â 1-As, [428][429][430] Si(100) 1 Â 1-S, 431,432 and Si(111) 1 Â 1-Cl, 433,434 fabricated in situ, different metals were deposited at cryogenic temperatures and occasionally in an inert gas environment. Since the ATS surfaces were known to be stable to various degrees and the metals were deposited "softly," the expectation was that the surface dipole on the ATS might survive the metal deposition and be available for SBH adjustment.…”

Tunable topological electronic structure of silicene on a semiconducting Bi/Si(111)-3×3substrate

“…[16][17][18][19][20][21] In particular, the structural model of Bi adsorbed on Si(111) has been investigated experimentally [22][23][24][25][26][27] as well as theoretically [25]. The well-known structural reconstruction proposed for the √ 3× √ 3R30…”