Atomic structure and electronic states of InAs(Sb)/GaAs submonolayer quantum dots

Summary form only given. Submonolayer-grown semiconductor nanostructures are promising for high power and high speed laser devices. They are formed by a cycled deposition of the active material with a thickness well below the critical thickness for Stranski-Krastanov transition and well below one monolayer (ML), alternating with several ML thick matrix material. They were successfully implemented in high speed (>25 Gbit/s) vertical-cavity surface emitting lasers operating up to 120°C. In this contribution, the structural changes upon additional supply of Sb are studied on the atomic scale using XSTM. The InAsSb agglomerations show slightly smaller sizes than equivalent submonolayer structures grown without Sb. The structural findings are in close correlation with the different band alignments of the electronic states, showing different behavior for electrons and holes.