Te growth of a low dislocation density relaxed GaSb bulk layer on a (001) GaAs substrate was demonstrated. The strain energy generated by the 7.78% lattice mismatch was relieved by a periodic array of 90° misfit dislocations. The misfit array was localized at the GaSb/GaAs interface and has a period of 5.6nm which was determined by transmission electron microscope images. No threading dislocations were visible. The misfits were identified as 90°, rather than 60°, using Burger’s circuit analysis, and were therefore not associated with generation of threading dislocations. A low dislocation density and planar growth mode was established after only 3 monolayers of GaSb deposition as revealed by reflection high-energy electron diffraction patterns. Calculations corroborate the materials characterization and indicated the strain energy generated by the 7.78% lattice mismatch was almost fully dissipated by the misfit array. The low dislocation density bulk GaSb material on GaAs enabled by this growth mode will lead to new devices, especially in the infra-red regime, along with novel integration schemes.

Strain Relief by Periodic Misfit Arrays for Low Defect Density GaSb on GaAs. S.H.Huang, G.Balakrishnan, A.Khoshakhlagh, A.Jallipalli, L.R.Dawson, D.L.Huffaker: Applied Physics Letters, 2006, 88[13], 131911 (3pp)