Oxidation as an assistant tool for structural analysis of inhomogeneous nanoscale InAs/AlAs(001) island system

Abstract

In the paper we present the structural and morphological investigation of an InAs/AlAs(001) island system under growth conditions where partial island coalescence takes place. To provide the structural analysis of elastically strained islands, new experimental X‐ray diffraction technique based on effect of islands oxidation is proposed and verified. It is found that both elastically strained and plastically relaxed islands coexist and have distinctly different sizes and chemical composition what can be explained by differences in their formation mechanisms. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

X-ray study of temperature dependent growth of InAs/AlAs(0 0 1) quantum dots

“…This means that the strained dots are composed not from pure InAs but from the In x Al 1−x As alloy [25]. From our previous studies the composition of strained dots grown under equal deposition conditions as the 500 • C-sample studied in this paper is close to In 0.8 Al 0.2 As [24]. Taking into account the observed compositional equality of all investigated samples, the determined Al-content can be correlated with the strained dots in all three investigated systems.…”

“…The intensity profile in Fig. 2 consists of three main intensity distributions: the substrate spot (I), the signal from elastically strained islands (II), and the signal from plastically relaxed clusters (III) [25]. The intensi- Label "I" marks the substrate peak position, "II" -marks signal from elastically strained islands, "III" -marks signal from plastically relaxed clusters.…”

“…For all samples the line scans in the radial [1 1 0] reciprocal space direction through the (2 2 0) GaAs Bragg reflections are shown in the logarithmic intensity scale in figure 2. The intensity profile in figure 2 consists of three main intensity distributions: the substrate spot (I), the signal from elastically strained islands (II) and the signal from plastically relaxed clusters (III) [24]. The intensities on the line scans are normalized by the intensity of the respective value of peak III (horizontal dashed line in figure 2).…”

Profiling the local carrier concentration across a semiconductor quantum dot

“…[20][21][22] For an oxidation layer to influence the thermoelectric voltage, it must have a significant value of S and a thickness greater than the phonon mean free path, i.e., >5 nm. For our samples, scanning tunneling spectroscopy reveals an effective band gap in excess of 2 eV, with the Fermi level positioned deep inside the gap (i.e., available electronic states are far from the Fermi level).…”