Reverse strain effects in the defect states in aluminium doped ZnO

ZnO was synthesised by the sol–gel method using zinc nitrate as the precursor. ZnO was doped with Al. Stress in the lattice was evident from the XRD peak shifts. A higher concentration of Al+3 showed a reverse strain effect also causing a reverse effect in the optical properties. An increase in crystallite size due to increased Al+3 was observed. A variation in absorption intensity based on the defect energy levels was observed. A difference in energy of the emission and absorption spectra resulting from defects in the material and non-radiative decay was seen. A change in the band gap was observed with changes in different dopant concentrations. These findings are useful for photocatalytic as well as antibacterial and anticancer treatments.