Excimer laser accelerated hydrothermal synthesis of ZnO nanocrystals & their electrical properties

The synthesis of ZnO nanocrystals is reported using a hydrothermal chemical growth technique combined with 248 nm nanosecond excimer laser heating at fluences in the range 0-390 mJ cm−2. The effect of laser heating in controlling the morphology of the nanocrystals is investigated using optical spectroscopy and electron microscopy characterization. Laser heating is shown to allow control of the crystal morphology from nanoparticles to nanorods as well as to modify the size distributions. The results indicate that not only does the laser accelerate the growth of nanocrystals, but can also produce crystals with a narrow size distribution possibly via photothermal size selection. An initial study of electrical conduction properties of ZnO nanocrystal thin films is also discussed.

Research highlights▶ An excimer laser has been used on the traditional hydrothermal growth of ZnO. ▶ The laser is used in order to accelerate the process as well as to control the morphology. ▶ The morphology is observed to be dependent upon the laser fluence. The fluence is also seen to control the size distribution ▶ Narrow size distributed ZnO nanocrystals have been achieved using a fluence of 330 mJ cm−2.