Diffusion effect-induced InNAs films growth on GaAs (100) substrates by MOCVD

Abstract Alloying formation of In(Ga)NAs epilayers has been realized on a GaAs (1 0 0) substrate during the InAs–InN metalorganic chemical vapor deposition (MOCVD) growth process, and the underlying mechanism is attributed to atomic interdiffusion effect. The Ga atoms in the epilayer are outdiffused from the GaAs substrate. By means of cross-sectional transmission electron microscopy, X-ray diffraction and secondary-ion-mass spectrometry techniques the samples with InAs prelayer thickness in the range of 25 nm–1.2 μm are characterized and the growth feature is clarified. It is thought that the defects such as vacancies and dislocations probably play a critical role in the diffusion process. Our experimental results also demonstrate that the outdiffusion of Ga atoms can be greatly suppressed with increasing the thickness of the underlying InAs epilayer, which leads to the InNAs alloy formation during the InAs–InN MOCVD growth.