Structural and optical investigation of (V, Al) doped and co-doped ZnO nanopowders: Tailored visible luminescence for white light emitting diodes

International audienceThis paper deals with co-precipitation synthesis and characterization of undoped, Al, V doped, and (Al+V) co-doped ZnO nanopowders. Complementary techniques are used: X-ray diffraction (XRD), transmission electron microscopy (TEM), diffuse reflectance and photoluminescence (PL) spectroscopies. XRD analysis revealed the formation of hexagonal-wurtzite structure for all samples. The average crystallite size decreases from 40 to 20 nm by doping ZnO NPs. TEM images showed quasi-spherical shaped nanoparticles. The UV-visible absorption spectra revealed that doping and co-doping induce slight red-shift of gap energy (3.29eV-3.27eV). The Urbach energy increases mainly with V doping, suggesting an increase in disorder and defects levels. PL spectra exhibit narrow and wide emissions in UV and visible regions respectively. Gaussian deconvo-lution of the broad visible peaks revealed several overlapped emissions. Mainly V incorporation in ZnO (single and double doping) notably improves visible luminescence. It leads to widening of the visible emission from 460 to 585 nm