Schematic illustrations of the (a) InP and (b) QW-capped samples, and (c) initial defect concentration profile, , as a function of position , and are respectively the QD position and the center position of the distribution relative to the surface.
(a) PL spectra at 77 K from as-grown and annealed LEII samples with a fluence of as a function of for . (b) PL spectra at 77 K from as-grown and annealed GID samples as a function of temperature for time . A typical example of the peak fitting operation is illustrated for the as-grown samples. Dashed lines illustrate the evolution of the various QD emission peaks, where the numeral in refers to the QD ensemble thickness in terms of an integer number of monolayers. Fine lines in (a) are magnifications of the spectra in that energy range.
Evolution of the QD emission peaks as a function of annealing temperature . In (a) and (b) are the evolution of the peak position and FWHM, respectively, for GID samples. In (c) and (d) are presented the evolution of the peak amplitude and FWHM, respectively, for LEII samples. The symbols correspond to the various QD ensembles with differing thickness.
PL spectra at 77 K from intermixed QD samples capped with (a) 200 nm and (b) 805 nm thick InP as a function of implantation fluence for annealing temperature and time . PL spectra at 77 K from as-grown QDs are also shown for comparison. Results of the peak fitting operation are illustrated for as-grown samples. Dashed vertical lines indicate the peak position of the various QD ensembles.
(a) PL spectra at 77 K from as-grown and intermixed (; , ) QDs in samples capped with pure InP (dashed lines) and a stack of compressively strained QWs (solid lines). PL spectrum at 77 K from an unimplanted InP capped sample (dotted line) annealed at for is also shown for comparison. (b) PL spectra at 77 K from as-grown and intermixed (; , ) QWs prior to wet chemical etching.
(a) Cross-sectional HAADF-STEM images of the as-grown QW stack. Higher magnification images of the first QW relative to the surface (b) prior to treatment and (c) after intermixing (; , ). (d) Line scan profiles across the intermixed QWs (; , ). A typical profile of an as-grown QW is also shown as a reference.
(a) Cross-sectional HAADF-STEM images ( zone axis) of a typical as-grown QD. Images of typical structures in GID samples after annealing for at (b) and (c) . Images of typical structures in LEII samples with a fluence of after annealing for at (d) and (e) .
Calculated hydrostatic strain distribution in the  plane of a 6 ML thick pure InAs truncated pyramid with (113) side facets on a 2 ML thick InAs WL buried in pure InP matrix. In the color scale, red and blue correspond to compressive and tensile strains, respectively.
Time integrated vacancy concentration at the QD layer as a function of calculated for with (solid line). These results are compared to those obtained for with (dotted line), (dashed line), and (dashed and dotted line).
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