Compositional variation in as-grown GaInNAs/GaAs quantum well structures

The variation of elemental composition in as-grown GaInNAs/GaAs quantum wel l structures has been investigated by energy dispersive X-ray analysis of c ross-sections using a high resolution scanning transmission electron micros cope. The formation of quaternary GaInNAs dot structures is indicated by lo w temperature photoluminescence measurements and by the correlation of indi um and nitrogen distributions. The distributions of arsenic and nitrogen ac ross the well structure suggest the presence of a continuous nitride-like l ayer formed at the surface of the GaAs buffer layer before the GaInNAs dots . The influence of this nitride-like interlayer on the mechanism of GaInNAs dot formation is discussed. (C) 2001 Elsevier Science B.V. All rights rese rved.