Low-temperature growth of self-assembled InAs dots on GaAs by MBE

Low-temperature (LT) MBE grown GaAs is of great interest due to its unique semiinsulating and ultrafast carrier recombination properties associated with the excess As incorporation during growth. Compared to bulk material and quantum wells we expect that the enhanced optical nonlinearity of quantum dots combined with the ultrafast optical response provided by LT growth will be useful for applications as ultrafast optical modulators and switches operating at low power. The main obstacle imposed for quantum dot formation at low temperature, however, is the small adatom migration length. Here we study the possibility of self-assembled InAs dot formation at low growth temperature on GaAs [100] and [311]A substrates and the extend to which strain effects and optimized growth conditions can outweigh the small adatom migration length for quantum dot formation.