Investigation on structural, morphological, optical and electrical features of nanocrystalline Zn1−xGdxO films synthesized by unconventional sol–gel screen-printing process

Nanocrystalline pure and gadolinium (Gd) doped zinc oxide (Zn 1− x Gd x O) films were synthesized on a glass substrate by unconventional sol–gel screen-printing process. The prepared samples were then fired (sintered) at 500 °C to get the desired stoichiometry. The samples thus prepared were analyzed for their structural, morphological, optical and electrical features by exploiting x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x-ray (EDX), UV–visible spectroscopy, photoluminescence (PL) spectroscopy and dark (DC) electrical resistivity appraised by two-probe unit. XRD analysis exposed that all the samples were polycrystalline in character exhibiting single-phase hexagonal wurtzite structure. Fiber-like surface morphology was exhibited by the samples. EDX technique indicates that the samples have the prerequisite constituent elements in stoichiometric ratio. The optical band gap (E g ) showed an increment from 3.24 to 3.45 eV on increasing the doping concentration of gadolinium from x = 0 to x = 0.05 illustrating a band gap tuning of 6.48%. PL spectra of prepared samples displayed a strong near band edge emission along with a weak green emission. Dark (DC) electrical resistivity was found to decrease with the increase in gadolinium doping concentration.