Self-assembled InAs quantum dots were incorporated into GaAs Schottky diodes. Defects were intentionally introduced by growing the quantum dots above the critical thickness for plastic relaxation. The strain-relaxed quantum dots introduce electrically active defects in n- as well as p-type diodes. Dislocation-induced defects and point defects were identified, and it could be shown that, in n-type GaAs, the EL6 defect played a major role in the relaxation of quantum dots. A comparison was made of the introduction of defects in strain-relaxed quantum dots grown by looped and non-looped deposition and depending upon an in situ annealing step. It was observed that looped deposited quantum dots were of better quality compared to non-looped quantum dots, even if they were grown beyond the critical thickness for plastic relaxation. The introduction of an annealing step after the growth of the quantum dots completely removed the defects in both quantum dot systems.

Dislocation-Induced Electron and Hole Levels in InAs Quantum-Dot Schottky Diodes. V.Polojärvi, A.Schramm, A.Aho, A.Tukiainen, M.Pessa: Physica E, 2010, 42[10], 2610-3