Special Effect of Urea as a Stabilizer in Thermal Immersion Method to Synthesis Porous Zinc Oxide Nanostructures

Abstract

ZnO nanostructure was prepared by catalytic immersion method (90°C) with zinc nitrate hexahydrate (Zn(NO3)26H2O) as a precursors and urea (CH4N2O) as a stabilizer. Different molarity concentration ratio of Zn(NO3)26H2O to CH4N2O, 2 : 1, 1 : 4, 1 : 6, and 1 : 8 is used in this work. The effect of urea concentration used during the synthesis process is discussed. The ZnO nanostructures were characterized by using field emission scanning electron microscope (FESEM), photoluminescene (PL), andI-Vprobe. Porous nanoflakes are successfully synthesized on p-type silicon substrate coated with gold layer with different size and dimension. High intensity photoluminescence (PL) at optimum concentration indicated that urea is good stabilizer to produce ZnO nanostructures with good crytallinity. Rectifying characteristics show dramaticaly change in turn-on voltage when the concentration of urea increases in aqueous solution. This is related to the theory about p-type doping of ZnO nanostructures by nitrogen from NH3.