Formation of dislocation defects in the process of burying of InAs quantum dots into GaAs

Determination of stress, strain, and elemental distribution within In(Ga)As quantum dots embedded in GaAs using advanced transmission electron microscopy

“…An elastic relaxation process leads to the formation of 3D island-like pyramidal QDs of square base with edges running parallel to h010i directions of the crystal matrix. 20 The exposed facets of the objects are generally of {101} type. 21 Without changing the processing temperature, the QDs were buried by overgrowing 30 nm of GaAs at a deposition rate of 0.3 nm/s.…”

Increased InAs quantum dot size and density using bismuth as a surfactant

“…30,31 Plan-view scanning tunneling microscopy images of uncapped QDs and XTEM images of buried QDs have suggested that with increasing InAs deposition, the combination of Ostwald ripening and diffusion of detached adatoms on the surface enables the growth of larger, dislocated islands at the expense of smaller QDs. [32][33][34][35][36][37] These islands are typically asymmetric, and the number of dislocations in the islands increases with island size. 38,39 Topographical AFM images of the QDs grown without and with a Bi surfactant are shown in Fig.…”

Misfit stress relaxation in composite nanoparticles

“…If, for example, f > 0, then the formation of the interstitial-type dislocation loop with the Burgers vector b 3 will lead to partial relaxation of the stress component r ð2Þ uu , while the formation of the vacancy-type dislocation loop with the Burgers vector b 4 to partial relaxation of the stress component r ð2Þ rr . These relaxation mechanisms are well known for some quantum dots and particle-reinforced composite materials (see references Bert et al, 2009;Chaldyshev et al, 2009;Kolesnikova et al, 2007 and references therein). Strictly judge the desirability of these scenarios in core-shell CNPs can only be based on an analysis of solutions of the appropriate boundary-value problems that are very complicated and still not resolved.…”