Stacked low-growth-rate InAs quantum dots studied at the atomic level by cross-sectional scanning tunneling microscopy

Abstract

Skolnick, M. S. (2003). Stacked low-growth-rate InAs quantum dots studied at the atomic level by cross-sectional scanning tunneling microscopy.

Composition profiles of InAs–GaAs quantum dots determined by medium-energy ion scattering

“…For the InAs-GaAs system, it is well established that ͑a͒ an alloyed InGaAs wetting layer ͑WL͒ is first formed during InAs deposition; 1 ͑b͒ the final state of the QDs may be an alloy even for deposition of pure InAs; 2 and ͑c͒ further changes to QD shape and composition take place during the capping of a QD array with GaAs or InGaAs. [3][4][5] These processes are controlled by a complicated combination of surface segregation 6 and locally strain-dependent surface migration and attachment. 5 Several experimental techniques have been used to probe the In distribution in QDs, including grazing incidence x-ray diffraction ͑XRD͒, 7 cross-sectional scanning tunneling microscopy ͑XSTM͒, 5,8 transmission electron microscopy ͑TEM͒ and scanning TEM energy dispersive x-ray analysis.…”

“…[3][4][5] These processes are controlled by a complicated combination of surface segregation 6 and locally strain-dependent surface migration and attachment. 5 Several experimental techniques have been used to probe the In distribution in QDs, including grazing incidence x-ray diffraction ͑XRD͒, 7 cross-sectional scanning tunneling microscopy ͑XSTM͒, 5,8 transmission electron microscopy ͑TEM͒ and scanning TEM energy dispersive x-ray analysis. 9 Both XRD and XSTM suggest that the In composition varies with height through the QDs, with pure InAs at the top of the QDs and progressively more Ga in the alloy towards the base of the QDs.…”

Numerical schemes for three-dimensional irregular shape quantum dots over curvilinear coordinate systems

“…, 3 denote the approximate eigenvalues obtained from the meshes described in the table. Figure 12 illustrates the convergence rates, rate [1] , rate [2] , and rate [3] , for all 10 target eigenvalues of the schemes S c , S s , and S m . From the figure, we see that all the convergence rates of S s and S m are close to 2.…”

“…From the figure, we see that all the convergence rates of S s and S m are close to 2. For S c , the rate [2] 's and rate [3] 's are close to 2; however, several rate [1] 's are less than 2. In short, all three schemes achieve second order convergence rates for fine grids.…”

“…Aiming at three-dimensional (3D) semiconductor quantum dots (QD) with irregular shape [3], we intend to develop simple yet efficient and accurate numerical schemes to compute all the bound state energies and the corresponding wave functions of the heterostructure. Numerical simulations of QDs have played an important role for investigating QDs' electronic and optical properties (e.g.…”