We monitored the difference intcof these two types of structures grown both on GaAs (311) B substrates by recording the dependence of intensity of one spotty pattern on the InAs coverage.
Until Sunday, the Jets were part of a nondescript pack, thanks to a spotty pattern of one step up, one step back, two steps up, one back.
Spotty patterns in the initial growth period were observed due to the large lattice mismatch between ZnTe and GaAs, and then they evolved into streaky and bright patterns.
The spotty pattern in the RHEED did not appear after the growth of the InAs QD layer, which implies that the actual deposition (total deposition − desorption) is slightly less than θc.
When the streak pattern turned into the spots of the three-dimensional (3D) QDs which demonstrated the transition of 2D 3D growth mode, the intensity of one spotty pattern was recorded.
Most of the Si-NCs are in a crystalline state, as evidenced by the lattice fringe shown in the HRTEM image as well as from the spotty pattern shown in the selected area of electron diffraction from one of the crystallites (Figure 1b).
When the spotty pattern appears (Figure 2b), the transformation of the 2D-3D growthasas occurred, and the deposition of InAs is defined as the critical thickness (θc).
The density of the InAs QDs is too high for the application of a single-photon source if the deposition of InAs is equal to θc adjusted by the transition of the RHEED pattern from reconstruction streaks to a spotty pattern.
Soon after, the spotty pattern sharpens and develops into a chevron pattern as shown by the evolution of the specular beam in Figure 2e; the latter is similar to those observed during epitaxial growth of quantum dots indicating the presence of facets [27].
The deposition of the SQD layer was in the critical condition when a spotty pattern just appears.
The streaky (spotty) pattern is associated with flat (rough) surfaces.
