Adequate UV photoemission from Ga2O3/ZnO/Ga2O3 thin film epistructures

Abstract

Epistructures of Ga2O3/ZnO/Ga2O3 were grown on c-Al2O3 substrate using pulsed laser deposition route. Thickness of ZnO layer varied to form these epistructures were investigated structurally, micro-structurally and optically using respective techniques. The modification made with the epistructures are observed to change the peak position of longitudinal optical phonon plasmon (LPP) i.e. A1(LO) mode of the wurtzite ZnO. The specific mode position observed suggests the presence of optical phonon confinement, defects and impurities present at the interface of the layer with others. However the photoluminescence spectra recorded on these epistructures showed quenching of unwanted visible emissions generally observed in device quality of ZnO and gallium oxide films/crystals is interesting. Further the temperature dependent PL investigations performed on selected specimens confirmed that the donor and acceptor excitonic emissions observed are purely governed by either the electron phonon interactions or due to the lattice dilation and the electron phonon interactions both, depending on the thickness of a sandwiched layer i.e. ZnO. The results observed herewith are encouraging considering use epistructures in thin film form to fabricate UV detectors where cost, repeatability and ease of manufacturing are one of the prerequisites. © 2023