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

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Abstract
The abruptness of InxGa1−xAs-on-GaAs as well as GaAs-on-InxGa1−xAs interfaces grown by molecular beam epitaxy is usually intrinsically limited by the surface segregation of indium atoms. The deposition of a one-monolayer-thick indium-rich prelayer of InGaAs (or of a submonolayer amount of InAs) prior to growth of InxGa1−xAs allows, however, the formation of a perfectly abrupt InxGa1−xAs-on-GaAs interface, as shown (for x=0.06 and x=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 GaAs-on-InGaAs interface so as to desorb surface indium atoms and suppress In incorporation in the GaAs overlayer. Both techniques preserve the optical quality of InxGa1−xAs/GaAs quantum wells.