Epitaxial strain engineering of luminescent properties in ZnGa2O4:Mn thin films

Epitaxial strain engineering of luminescent properties in ZnGa2O4:1%Mn thin films was demonstrated by changing both the O2 gas pressure in the deposition chamber and the film thickness. Films were prepared under pressures of 0.2 and 100 mTorr. While, for low-pressure films, the residual strain was constant, for high-pressure films, it relaxed as the thickness of the film increased. Emission spectra showed green emissions ascribed to energy transitions in Mn2+. Although invariant for low-pressure films, the emission peak blueshifted as film thickness increased for high-pressure films. Further investigation revealed the residual strain as the underlying cause of this blueshift.