Determination of optical band gap of ZnO:ZnAl_2O_4 composite semiconductor nanopowder materials by optical reflectance method

摘要

ZnO:ZnAl_2O_4 composite semiconductor nanopowder materials were synthesized by sol gel method. X-ray diffraction results reveal that Al doped ZnO samples have a polycrystalline hexagonal structure with a=3.2506 A, c=5.2079 A lattice parameters. The crystallite size of the ZnO samples is decreased with increasing Al content. Atomic force microscope results indicate the presence of microanohexagons with different sizes from 128 to 166 nm. Optical band gap of the ZnO samples is decreased and reaches a low value of 2.82 eV for 20% Al. The electrical conductivity dependence of temperature confirms that ZnO:ZnAl_2O_4 composite semiconductor nanopowder materials exhibit semiconductor behavior.