Influence of hole shape/size on the growth of site-selective quantum dots

Abstract

The number of quantum dots which nucleate at a certain place has to be controllable for device integration. It was shown that the number of quantum dots per nucleation site depends on the size of the hole in the substrate, but other dimensions of the nucleation site are vague. We report on the influence of hole shape on site-selectively grown InAs quantum dots (QDs) by molecular beam epitaxy. Dry etching of the GaAs wafers was used because of its high anisotropic etching characteristic. Therefore, it was possible to verify the influence of several hole shape parameters on the subsequent QD growth independently. We show that the nucleation of these QDs depends on several properties of the hole, namely its surface area, aspect ratio of the surface area, and depth. Especially, the aspect ratio shows a big influence on the number of nucleating QDs per site. With knowledge of these dependencies, it is possible to influence the number of QDs per site and also its distribution.

Nanoscale wafer patterning using SPM induced local anodic oxidation in InP substrates

“…Table 1 shows a comparison between the nanohole depths used for the site-controlled growth of InAs QDs on GaAs. A range of techniques are In this study, we observed a low standard deviation (SD) in nanohole radius and depth which is an encouraging result for reducing inhomogeneity in site-controlled QD size, emission wavelength and occupancy [27,28]. The SD in radius was between 15 and 3 nm, with no trend seen when increasing voltage or humidity.…”

Morphological Evolution of Pit-Patterned Si(001) Substrates Driven by Surface-Energy Reduction

“…As the actual shape of pits does influence the energy of the system and, more in general, island nucleation [ 26 , 27 ], it is crucial to control their morphology. This is not trivial: after all, pits are just holes drilled into the substrate.…”

The Role of Groove Periodicity in the Formation of Site-Controlled Quantum Dot Chains

“…In molecular beam epitaxy (MBE) processes, this can be achieved by defining the nucleation sites for impinging atoms using patterning the surface. Patterning is usually accomplished by lithographic techniques, such e-beam lithography [7][8][9][10][11], nanoimprint lithography [12], interference lithography, photolithography [13], or atomic force microscopy (AFM) lithography [14].…”