Growth of InGaAs/GaAs quantum wells with perfectly abrupt interfaces by molecular beam epitaxy

摘要

The abruptness of InxGa1minus;xAshyphen;onhyphen;GaAs as well as GaAshyphen;onhyphen;InxGa1minus;xAs interfaces grown by molecular beam epitaxy is usually intrinsically limited by the surface segregation of indium atoms. The deposition of a onehyphen;monolayerhyphen;thick indiumhyphen;rich prelayer of InGaAs (or of a submonolayer amount of InAs) prior to growth of InxGa1minus;xAs allows, however, the formation of a perfectly abrupt InxGa1minus;xAshyphen;onhyphen;GaAs interface, as shown (forx=0.06 andx=0.11) by a detailed study of the surface composition at various stages of the growth of this heterostructure. A thermal annealing can also be performed at the GaAshyphen;onhyphen;InGaAs interface so as to desorb surface indium atoms and suppress In incorporation in the GaAs overlayer. Both techniques preserve the optical quality of InxGa1minus;xAs/GaAs quantum wells.