A double-layer heterostructure with embedded into single-crystal silicon matrix nanocrystals (NCs) of gallium antimonide (GaSb) was grown. The NCs were formed by solid phase epitaxy method using 1.6-nm-thick Ga-Sb stoichiometric mixture and annealing at a temperature range of 200–500 °C. The embedded NCs have a concentration of about 5.4 × 1010 cm− 2, a mean height of 8.6 nm and a mean lateral dimension of 19.2 nm. A stress induced inside the NCs owing to lattice mismatch between Si and GaSb was fully relaxed by edge dislocations at Si/GaSb interface. All the NCs have identical epitaxial relationship: GaSb(111)||Si(111), GaSb11−0 ||Si11−0.