Improved thermal stability of GaAs/AlGaAs single quantum well by Zn out-diffusion from Zn doped GaAs substrate

We report the effects of n-type doping by Si and p-type doping by Zn in the GaAs substrate on the thermal intermixing of undoped GaAs/Al/sub 0.24/Ga/sub 0.76/As single quantum well (QW) structures. For comparison, semi-insulating GaAs substrate was also used. The samples with Si-doped GaAs substrate and semi-insulating GaAs substrate show blue shifts that are in agreement with thermal stability studies by other workers. The sample with Zn-doped GaAs substrate, however, shows clear evidence of suppressed intermixing by Zn diffusion from the substrate into the QW structure. The enhanced thermal stability of the GaAs/Al/sub 0.24/Ga/sub 0.76/As QW structure is attributed to a Zn-diffusion induced reduction in the number of column-III vacancies in the QW structure.