Tunable UV-Luminescent MgZnO Nanoalloys

Mg(x)Zn(1-x)O alloys are promising wide-bandgap semiconductors for optoelectronic applications, and also of considerable interest from a fundamental viewpoint. The environmentally friendly chemical composition and the deep excitonic level $\sim $ 60 and 90 meV of ZnO and MgO respectively make it an excellent candidate for high-efficiency next generation ultraviolet light sources. These optical alloys may enable the tuning of the bandgap and the luminescence at the range of $\sim $ 3.0 for ZnO of the wurtzite structure up to $\sim $ 7 eV for the MgO of the rocksalt structure. We will present studies on the photoluminescence and Raman properties of Mg(x)Zn(1-x)O nanocrystallites of average size $\sim $ 30 nm that were synthesized via the thermal decomposition method. For the studied composition range of 0-26{\%} Mg, the room temperature UV-PL was found to be tuned by $\sim $ 0.3 eV towards the UV-spectral range. For that composition range the first-order LO Raman mode was found to exhibit a significant blueshift of $\sim $ 33 cm$^{-1}$ indicating that a good solid solution was achieved at the nanoscale. At higher composition ranges a PL blue shift of at least 1.3 eV was achieved. Issues such as excitonic emissions, alloy spectral broadening, and phonon symmetry will be presented