EFFECTS OF SEGREGATION ON THE OPTICAL-PROPERTIES OF (IN,GA)AS GAAS QUANTUM-WELLS GROWN BY MBE UNDER VARIOUS CONDITIONS/

Thermally detected optical absorption measurements have been performed at liquid helium temperature in order to study the effects of In segr egation on the optical properties of InxGa1-xAs/GaAs quantum wells gro wn by molecular-beam epitaxy under various growth conditions. The expe rimental data are analysed using a kinetic model explicitly including the growth parameters. The variation of the In surface segregation wit h substrate temperature and growth rate is investigated. This work dem onstrates that a way to limit segregation is to prevent the system fro m reaching thermodynamic equilibrium by choosing low growth temperatur es or high growth rates. It is shown, however, that growth temperature is the most efficient parameter to kinetically limit the exchange pro cess. (C) 1997 Elsevier Science S.A.