Suppression of interdiffusion in In/sub 0.5/Ga/sub 0.5/As/GaAs quantum dots

In this work, Ga-doped spin-on glass (SOG) film and electron beam evaporated titanium dioxide (TiO/sub 2/) film were deposited onto a In/sub 0.5/Ga/sub 0.5/As/GaAs quantum dot (QD) structure in order to suppress the interdiffusion. It is demonstrated that Ga-doped SOG was only able to restrict the occurrence of impurity free vacancy disordering which is promoted by normal SiO/sub 2 /film, however the TiO/sub 2/ film suppressed the thermal intermixing due to the thermal stress effect and possibly metallurgical reactions between GaAs and TiO/sub 2/.