Angular distribution ofGa+ions desorbed by 3-keV-ion bombardment of GaAs{001}-(2×4)

Atomic placement of Al on the GaAs {001}c(4×4)reconstruction determined by angle-resolved secondary-ion mass spectrometry

“…It has been shown in previous studies that the Si PES adequately, though only qualitatively, describes the angular distributions of GaAs and Al/GaAs systems because the desorption mechanisms are more dependent on atomic positions than on mass or chemical environments of the atoms in the lattice. 25,27,35,36,41,45 Three different Al adsorption sites on the c(4ϫ4) reconstruction, shown in Fig. 1, were modeled with MD calculations using a Si ͕001͖ c(4ϫ4) reconstruction to identify desorption patterns of adsorbate and surface atoms.…”

Submonolayer structure of an abrupt Al/GaAs{001}-(2×4) interface

“…The origin of the features associated with the Ga ϩ ion distribution from the clean surface have been described in detail with the aid of molecular-dynamics ͑MD͒ computer simulations of the ion-bombardment event. 25 Briefly, the two largest peaks arise solely from a direct collision between a 3rd layer As atom and a 2nd layer Ga atom causing Ga ϩ -ion ejection along their common bond direction. The shoulders and other features at higher values of the polar angle, ⌰, arise from a mix of mechanisms related to the missing row of As 2 and to the formation of the As dimer itself.…”

“…We have recently shown, however, that it is possible to employ a many-body Si potential developed by Tersoff, 34 to elucidate the mechanistic pathways that give rise to the major features in the angular distribution. 25,32,35 In particular, orresponds to the ͗110͘ crystal direction. The intensities have been multiplied by sin ⌰ to yield the probability densities.…”

“…The experiments were performed in an ultrahigh vacuum ͑UHV͒ complex consisting of a Riber 2300 molecular-beam epitaxy ͑MBE͒ system and a surface analysis chamber equipped with low-energy electron diffraction ͑LEED͒ and angle-resolved SIMS. 16,25 The GaAs͕001͖ wafers were spin etched in a 10:1:1 solution of H 2 O:H 2 O 2 :NH 4 OH for 20 s rinsed in distilled water, and bonded to a Mo block with In before insertion into the vacuum system. The native oxides were removed in vacuum by heating to 900 K under As 4 flux.…”

Defect formation inSi(111)7×7surfaces due to 200 eVAr+Ghose1, Robinson2, Averback3 2003Phys. Rev. B3010View full textAdd to dashboardCite

“…These surface defects are populated by adatom vacancy regions, where adatoms have been removed by ion impact. The possibility of sputtering from second and third layer of atoms has been demonstrated by molecular-dynamics simulation 15 and experiment 16 on different semiconductor surfaces. For our range of energy, the ion range and energy distribution is expected to extend beyond ϳ6 Å , 17 so there is a possibility of displacement of atoms below the surface layers.…”