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We present a self-consistent modelfor the Zeldovich nucleationrate that determines the nucleation probabilities, growth rates, andeven the preferred crystal structure of Au-catalyzed III–Vnanowires fabricated by the vapor–liquid–solid growthmethod. The obtained expression accounts for the nucleation kineticsin ternary Au–III–V alloys and shows that the nucleationrate in vapor–liquid–solid nanowires is proportionalto the As concentration, As diffusion coefficient in the droplet,and activity of solid GaAs. The leading exponential term of the nucleationrate is modified due to the self-consistency renormalization. As aresult, the behavior of the effective nucleation barrier versus Gaconcentration is changed significantly with respect to the commonlyused expression. This strongly affects the values of Ga concentrationsduring growth which are obtained within the self-consistent approachwith the known nanowire elongation rates. In turn, the renormalizednucleation rates change the predictions regarding the zincblende–wurtzitephase transitions in III–V nanowires. In particular, our calculationsshow why the Au-catalyzed GaAs nanowires grown by molecular beam epitaxyat 550 °C are predominantly wurtzite, while the high temperaturehydride vapor phase epitaxy at 715 °C yields pure zincblendecrystal structure. We also obtain useful estimates for the As diffusioncoefficients in ternary Au–Ga–As liquids at differentconditions. [ABSTRACT FROM AUTHOR]

The optical properties of quantum dot arrays in the MBE-grown InAs/GaAs(100) epitaxial system with an effective InAs layer thickness of 1.9 monolayers were studied in samples exposed to the beam of As4 for various times after switching off the In beam. The results of photoluminescence measurements showed that the emission wavelength increased with the exposure time within certain limits. This behavior agrees with predictions of the kinetic model of the initial stage of quantum dot formation. [ABSTRACT FROM AUTHOR]

Ensembles of InAs quantum dots formed at the GaAs(100) surface have been studied by the methods of reflection high-energy electron diffraction and photoluminescence. The amount of deposited InAs corresponds to a wetting layer thickness smaller than the critical value necessary for the transition from two- to three-dimensional growth. It is experimentally shown that, at a deposited film thickness of 1.5 and 1.6 monolayers, islands are formed after keeping the sample in a flow of As[sub 4] . The influence of the substrate temperature on the kinetic characteristics of the formation of InAs/GaAs islands has been studied. © 2003 MAIK “Nauka / Interperiodica”. [ABSTRACT FROM AUTHOR]