In situ scanning tunneling microscopy of InAs quantum dots on GaAs( 0 0 1 ) during molecular beam epitaxial growth
Abstract Arrays of InAs quantum dots (QDs) have been studied using in situ scanning tunneling microscopy (STM) during their growth by molecular beam epitaxy on GaAs(0 0 1). At a substrate temperature of 400 °C under As 4 flux, both the QDs and the underlying step-terrace structure of the wetting layer (WL) are found to be static, with neither step-flow nor QD ripening observed. Higher resolution images of the mature WL show slightly different [1 1 0] periodicities to those observed in quenched STM studies.
ISLAND NUCLEATION AND GROWTH ON RECONSTRUCTED GAAS(001) SURFACES
The initial stages of homoepitaxy on GaAs(001) are studied with atomic-resolution scanning tunneling microscopy and Monte Carlo simulations that include the zinc blende structure of GaAs, the (2 3 4) reconstruction of the (001) surface, and the kinetics of As 2 incorporation. The reconstruction is found to favor nucleation on the top-layer arsenic dimers and to cause small islands to be unstable until they adopt the local (2 3 4) structure. [S0031-9007(98)06564-8]
Photoreflectance characterization of vanadium-doped GaAs layers grown by metalorganic vapor phase epitaxy
Abstract We characterized the vanadium-doped (GaAs:V) layers grown on GaAs substrate by metalorganic vapor phase epitaxy. The conductivity of the samples is checked by the Hall effect measurements, and it is n type with electrons concentration ranging from 2×10 13 to 2×10 17  cm −3 . We used the photoreflectance technique (PR) to study the effect of vanadium doping on the optical properties of GaAs. Our experimental results show that the built-in electric field F and the broadening parameter Γ 0 increase with V-doping concentration. Furthermore, the temperature dependence of the built-in electric field and the broadening parameter of GaAs:V samples have been investigated by PR. It has been observed that these parameters increase with increasing temperature. The decrease of the built-in electric field with decreasing temperature is due to the photovoltage effect.We characterized the vanadium-doped GaAs (GaAs:V) layers grown on GaAs substrate by metalorganic vapor phase epitaxy.