Positron annihilation spectroscopy was used to investigate the role of vacancies in the interdiffusion of Al and Ga in AlSb/GaSb superlattices. The samples were grown by metalorganic vapor-phase epitaxy on undoped and Te doped GaSb and consisted of 10 periods of GaSb quantum wells (thickness of 13nm) and AlSb barriers (thickness of 2 to 3nm) and an approximately 50nm-thick capping layer of GaSb. The superlattices were annealed (908K, up to 250s), resulting in interdiffusion of Al and Ga between well and barrier. A secondary ion mass spectrometry study showed that the Te dopant diffused from the substrate through the superlattice structure in the annealing process. In the positron annihilation study, it was observed that the vacancy concentration clearly decreased with annealing for the samples grown on undoped substrates, whereas the samples grown on Te doped substrates exhibited a different annealing behavior.

Influence of Substrate Doping and Point Defects on Al and Ga Interdiffusion in AlSb/GaSb Superlattice Structures. J.Slotte, M.Gonzalez-Debs, T.F.Kuech, J.G.Cederberg: Journal of Applied Physics, 2007, 102[2], 023511