Design and realization of low density InAs quantum dots on AlGaInAs lattice matched to InP(001)

Abstract

a b s t r a c tWe present detailed growth studies of InAs nanostructures grown on Al x Ga y In (1 À x À y) As lattice matched to an InP(0 0 1) substrate using molecular beam epitaxy. Highly elongated quantum dash like structures are typically favoured in this material system, due to very anisotropic migration lengths along the [1 À 1 0] and [1 1 0] directions. In order to increase the short migration length along the [1 1 0]-direction we used ultra low growth rates down to 3 Â 10 À 3 monolayers per second. We show that this offers the possibility to form InAs quantum dots with a low surface density, in contrast to the most commonly formed quantum dash structures. To tailor the emission wavelength of the quantum dots, three methods were studied: (i) the variation of the bandgap of the surrounding material by adjusting the aluminium to gallium ratio, (ii) the variation of the bandgap of the quantum dot material by incorporating antimony and (iii) the variation of the height of the quantum dots by closely stacking two layers of quantum dots upon each other.

Generation of Non‐Classical Light Using Semiconductor Quantum Dots

“…Depending on the growth conditions, In(Ga)As/GaAs QDs typically emit in the range 900-1300 nm. To obtain InAs QDs emitting in the telecommunication C-band (1530-1565 nm) the lattice mismatch has to be reduced which can be achieved by using InP or AlGaInAs as the substrate [29][30][31]. In addition, it was recently demonstrated that metamorphic InGaAs strain-relaxation layers can also be used to shifts the emission of InAs QDs into the C-band [32].…”

Growth temperature dependence of cubic GaN step structures and cubic InN dot arrays grown on MgO (001) vicinal substrates

“…Similar elongated dots or wirelike nanostructures are frequently observed in other material systems, and this originates from anisotropic stress and anisotropic migration length of adatoms along different crystal directions. 30,31) Two kinds of lateral orientation can be found in these elongated c-InN dots, that is, the dots oriented with the long axis parallel and perpendicular to [110] MgO (the substrate off-cut direction). Differences were observed in the lateral size and preferential direction of the lateral orientation depending on the substrate off-cut angle.…”

Growth of InAs quantum dots and dashes on silicon substrates: Formation and characterization

“…It seems that a reduction of the formation time can switch the InAs QDs shape from circular to dashed-like InAs; this dash structures is preferentially oriented on the (1 1 0) crystal direction. This is due to the preferential migration of indium atoms along the (1 1 0) crystal direction, which results from the anisotropic migration lengths and anisotropic stress relaxation along different crystal directions [14,15].…”