Nanostructured zincoxide (ZnO) was synthesized via a sonochemical method. The effect of the duration of ultrasonic irradiation in a continuous mode on the generated particles was investigated. Additionally, the effect of flowing either air or nitrogen during the sonication process was investigated. Zinc nitrate and
ammonia water-based solutions were selected as chemicals without the addition
of other surfactants. The generated particles indicated that a wurtzite
structure of ZnO in a hexagonal phase was formed with a crystalline size that increased
as the ultrasound irradiation time increased. The morphology of the generated
ZnO particles could be changed from flowerlike to needlelike structures via
continuous ultrasound irradiation over one to two hours, resulting in increases
in the particle lengths and decreases in the particle diameters from 200 to 80
nm. Photoluminescence intensity was also increased with increases in the ultrasonic
irradiation times. Photoluminescence spectra were also influenced by the
atmospheric environment. Two bands centered at 390 and 500 nm were generated
under a nitrogen environment. On the other hand, a single wide band with a peak
at around 430 nm was found for particles generated under an air environment. It
can be applied for light emitting diodes (LED) or laser fabrication with a
controlled emitting band.
