Cubic InxGa1−xN/GaN quantum wells grown by Migration Enhanced Epitaxy (MEE) and conventional Molecular Beam Epitaxy (MBE)

Abstract

We report the growth of InxGa1−xN/GaN quantum wells (QWs) in metastable-cubic phase through two well-controlled methods, Migration Enhanced Epitaxy (MEE) and conventional Molecular Beam Epitaxy (conventional MBE) on GaAs substrate. An increment of In mole fraction in the c-InxGa1−xN QWs was found with the decrease of growth temperature for both methods. The MEE implemented in this work, which consists of alternating the atomic flux periods at temperatures, approximately 100 ∘C lower than in conventional MBE, successfully addresses the cubic InxGa1−xN/GaN QW growth challenge. The QWs grown by this method present lower In segregation than those grown using conventional MBE. Excitonic transitions in the visible spectrum range from violet (414 nm) to green (544 nm) wavelengths were obtained in the QWs, by varying In content for both methods. These excitonic emissions are in good agreement with the theoretical calculations performed. Likewise, we identified the chemical bonds present in each c-InxGa1−xN QW, which corresponded to In–N and Ga–N, and their binding energies through In 3d, Ga 3d, and N 1s core levels by x-ray photoelectron spectroscopy (XPS). Therefore, this work provides an important understanding of In segregation, In incorporation mechanism, and radiative excitonic transitions of cubic QWs, that can be considered in complex heterostructures for novel optoelectronic applications.