Scanning tunneling microscopy study of interfacial structure of InAs quantum dots on InP(001) grown by a double-cap method

摘要

The interfacial properties of InAs self-assembled quantum dots (QDs) on InP(001) grown by the double-capped method by metal-organic chemical-vapor deposition have been investigated by means of cross-sectional scanning tunneling microscopy (STM). Truncated pyramidal QDs with a monolayer-step height in the range of 6-14 ML are observed in the STM images, and their top and bottom interfaces are extremely sharp. On the side of the QDs, however, segregation of As atoms is observed, which suggests that the migration of As atoms from the QDs takes place by As/P exchange during the cap and etching processes in the double-cap procedure.