Dielectric mismatch effects on the electronic and optical properties of GaN∕HfO2 quantum wells

Abstract

In this work, we demonstrate that the image charges effect induced by the dielectric mismatch strongly modifies the electronic structure of GaN∕HfO2 quantum wells (QWs) in such a way that the ideal QW confinement model is no longer suitable for the description of these systems. Particularly, two different confinement regimes were observed for narrow and wide QWs. In the former, electrons, light and heavy holes are spatially localized in the same region. In wide QWs, heavy holes are confined in the interfacial regions due to the strong attraction of the image charges, which does not occur for electrons and light holes. As a consequence, optical transitions involving electrons and heavy holes become less efficient in wide QWs.