Visible photoluminescence in ZnO tetrapod and multipod structures

The investigation of the properties of ZnO tetrapod and multipod structures using scanning electron microscopy, X-ray diffraction, photoluminescence (PL) and electron paramagnetic resonance (EPR) spectroscopy was discussed. The ZnO samples were fabricated by heating a mixture of ZnO, GeO₂ and graphite at 1100°C in order to modify the morphology of the fabricated structures. The room temperature of PL was measured by using a HeCd laser excitation source (325 nm). It was found that the green PL was due to transition between a shallow donor and deep acceptor in the absence of g ≈ 1.96 EPR signal and transition between the conduction band and deep acceptor in the absence of g ≈ 1.96 EPR signal.