Nanofabricated quantum dot array formation through annealing of nano-patterned planar InAs
Relative volume of quantum dots compared to a 25 nm base width pyramid, which would be formed from various grid geometries. The various lines correspond to constant volume plots. The number associated with the line is the relative volume.
2 μm × 2 μm AFM images of annealed planar InAs patterns produced using (a) 75 and (b) 100 lines per pattern. The corresponding areas are shown in (c) and (d), and height distributions are shown in (e) and (f).
High resolution transmission electron micrograph of our planar InAs layer is shown here. The associated Lomer dislocations are indicated by white arrows. The inset in the upper left shows the magnified image around the core of the dislocation. For this film, the average spacing between Lomer dislocations is ∼7.4 nm. The distance between atomic positions along the interface is 0.4 nm.
Bright field (G = 220) cross-sectional TEM of a planar InAs region after annealing (images taken with a TEM operated at 300 kV). The GaAs substrate is located at the lower left of the image and the InAs TSBPs are shown in the middle of the image (three are highlighted with arrows). No strain fields from dislocations are apparent in the GaAs substrate at the interface between the GaAs and InAs features (WL and InAs TSBP). In addition, no apparent damage is visible in the InAs TSBP.
(Color) Images acquired from μPL mapping for various patterns on the sample. The maps were taken with ∼1 μm steps, which causes the apparent pixilation. (a) Confocal optical image of the mapped area. Image (b) has an overlaid map for intensity of peak at 914 nm. The color scale ranges from 400 for blue up to 800 for red. Image (c) has overlaid map for intensity of peak at 1040 nm. The color scale ranges from 200 for blue up to 475 for red.
AFM analysis of the QD distribution.
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