Size Distribution and Scaling Behavior of InAlAs/AlGaAs Quantum Dots Grown on GaAs by Molecular Beam Epitaxy

Abstract

We studied the size distribution and its scaling behavior of self-assembled InAlAs/AlGaAs quantum dots (QDs) grown on GaAs with the Stranski-Krastanov (SK) mode by molecular beam epitaxy (MBE), at both 480°C and 510°C, as a function of InAlAs coverage. A scaling function of the volume was found for the first time in ternary alloy QDs. The function was similar to that of InAs/GaAs QDs, which agreed with the scaling function for the two-dimensional submonolayer homoepitaxy simulation with a critical island size of i = 1. However, a character of i = 0 was also found as a tail in the large volume.

Size distribution of islands according to 2D growth model with 2 kinds of diffusion atoms

“…This means that these island distributions experience size dispersion in the case of large islands, where s/S > 2. Here, we note that this feature is similar to our previous experiments on InAlAs QDs [3].…”

Morphology and valence band offset of GaSb quantum dots grown on GaP(001) and their evolution upon capping

“…Indeed, the QD volume determination from AFM images can suffer from an overestimation. But as discussed by Ebiko et al [24] and Lu et al [25], such rather systematic error does not impact the scaling function Therefore, the strain arising from the high mismatch between GaP and GaSb (11.8%) does not modify the scaling function of the QDs as already observed in the InAs/GaAs material system for which the mismatch is lower (7.2%). This result then further extends the validity of such a theory to highly mismatched systems.…”

“…This theory has been successfully applied to the homoepitaxial growth of Fe [21], of GaAs on different GaAs surfaces [22], but also to the 2D InAs heteroepitaxy on GaAs [23]. It has been further extended to 3D growth of InAs QDs on GaAs [24] and InAlAs on AlGaAs [25]. Analytical forms of the island distribution scaling function have been derived by Amar et al [26] for critical island size i of 1, 2 and 3 atoms.…”

“…Figure 6 shows the volume distribution scaling function for a growth temperature of 450 °C, i.e. below the growth temperature for which coalescence occurs (470 °C) together with the calculated ones according to the formula of Amar et al These curves have been calculated in the same way as in [25], with θ eff standing for the total QD volume. It evidences the rather good agreement between the experimental data and the theoretical distribution function assuming i=1.…”

Atomic-scale characterization of single and double layers of InAs and InAlAs Stranski-Krastanov quantum dots

“…InAlAs layers have already been extensively investigated when lattice matched to InP substrates (In 0.52 Al 0.48 As), as it can serve as a barrier to lattice-matched In 0.53 Ga 0.47 As [27], but it can also be used as a metamorphic buffer on GaAs substrates [28] for device applications. However, there are only sporadic studies about InAlAs QDs grown on GaAs [29][30][31][32][33], and just a few more about InAlAs layers used as a barrier or confinement layer for InAs QDs deposited on GaAs [34,35].…”