Relaxation behaviour of highly strained GaAs/InxGa1-xAs/GaAs-quantum wells depending on MOVPE growth conditions

For highly strained GaAs/In_xGa_1-xAs/GaAs-quantum wells (QWs) with × ≥ 0.25, grown by metalorganic vapour deposition (MOVPE), the relaxation with increasing layer thickness does not take place in the classical way via elongated misfit dislocation formation. Already below the critical layer thickness a transition of the growth mode from step flow mode to the Stranski-Krastanov growth mechanism is observed resulting in formation of clusters with a higher In concentration than the surrounding material.