Dislocation-induced spatial ordering of InAs quantum dots: Effects on optical properties

Abstract

Improved optical properties of InAs quantum dots grown with an As 2 source using molecular beam epitaxy J. Appl. Phys. 100, 063107 (2006) Misfit dislocations were used to modify the surface morphology and to attain spatial ordering of quantum dots ͑QDs͒ by molecular beam epitaxy. Effects of anneal time and temperature on strain-relaxed In x Ga 1Ϫx As/GaAs layers and subsequent spatial ordering of InAs QDs were investigated. Photoluminescence ͑PL͒ and time-resolved PL was used to study the effects of increased QD positional ordering, increased QD uniformity, and their proximity to dislocation arrays on their optical properties. Narrower inhomogeneous PL broadening from the QDs ordered on dislocation arrays were observed, and differences in PL dynamics were found.

Lateral self-arrangement of self-assembled InAs quantum dots by an intentional-induced dislocation network

“…We attribute these lines to preferred SAQD generation along the MDN. This is due to the strain field on the surface induced by the underlying misfit dislocation providing favored nucleation places for indium atoms [5,8,9]. This effect is a kind of defect decoration and allows us to determine the defect density from AFM data.…”

“…As an alternative approach to the lithographic techniques, we study in this paper the ordering of SAQDs induced by a misfit dislocation network (MDN). Recently, Leon et al demonstrated spatial ordering of self-assembled quantum dots using misfit dislocations [5]. This technique provides the advantage that the pre-treatment for site control is entirely done in the growth chamber, and no lithographic steps are necessary.…”

Ordering growth of InAs quantum dots on ultra-thin InGaAs strained layer

“…For low-strained system, dislocations will first generate in the epilayer/ substrate interface when the epilayer exceed a certain thickness. These dislocations have special directions, so people want to use them to fabricate ordered QDs [4,5]. For example, Fumito Hiwatashi [4] found InAs QDs mainly aligned along [1][2][3][4][5][6][7][8][9][10] on InGaAs layer and thought that was because QDs prefer nucleating in the strainrelaxed regions of the strained layers.…”

Electrical control of a laterally ordered InAs/InP quantum dash array

“…However, the fabrication of large, optically active, quantum dot arrays still remains a challenging task. In the last years, quantum dot arrays or chains have been fabricated combining self-assembling methods with different patterning processes, 13,14,15,16,17 strain engineering of the substrate, 18,19 inclusion of misfit dislocations, 20,21 or cleaved edge overgrowth processes 22 . The optical quality of these QDs has been assessed by characterization of their ensemble photoluminescence, and increasing efforts are being directed to investigate the properties of individual QDs in the array 17,22 or to control them by applying a lateral electric field.…”