Effect of urea as a stabiliser in the thermal immersion method to synthesise zinc oxide nanostructures on porous silicon nanostructures

摘要

In this work, ZnO nanostructures were prepared using the catalytic immersion method (90 °C) with zinc nitrate hexahydrate (Zn(NO_3)_26H_2O) as a precursor, urea (CH4N2O) as a stabiliser and porous silicon nanostructures (PSi) as a substrate. PSi prepared on p-type Si by using electrochemical etching method. Different molarity concentration ratios of Zn(NO_3)_26H_2O to CH_4N_2O (2:1, 1:2, 1:4 and 1:6) were used in this work. The effects of the urea concentration during the synthesis process were discussed. The ZnO nanostructures were characterised using field emission scanning electron microscope (FESEM), photoluminescence (PL) and I-V probe. Porous nanoflakes were successfully synthesised on a p-type PSi substrate that was prepared by electrochemical etching. High-intensity photoluminescence (PL) at the optimum concentration indicated that urea is a good stabiliser to produce ZnO nanostructures with good crystallinity. The high resistance of ZnO/PSi show that electrical properties of PSi dominant compare to ZnO nanostructures.