Enhanced visible emission from vertically aligned ZnO nanostructures by aqueous chemical growth process

ZnO nanostructures consisting of nanowires and nanorods have been grown by aqueous chemical growth (ACG) process on the ZnO seed layers. ACG process has been carried out for 5 h and 15 h to obtain the one dimensional nanostructures. This ZnO nanostructure comprises mixture of vertically aligned nanorods and nanowires. Structural analysis reveals that the crystal orientation is along (002) plane exhibiting a hexagonal wurtzite structure. The crystallinity of ZnO nanostructures increases after aqueous chemical treatment with respect to the growth duration. Optical studies revealed that when the duration of aqueous chemical treatment is increased, the transmittance of the films decreases considerably. The as-deposited ZnO seed layers exhibit electron carrier concentration of 4.69×10¹⁴ cm⁻³ and the value increases to 9.44×10¹⁵ cm⁻³ after 5 h and 1.53×10¹⁶ cm⁻³ after 15 h of aqueous chemical treatment. It has been observed that ZnO nanostructures exhibit enhanced luminescence properties in visible region which covers the entire visible region of the spectrum. - Highlights: • Mixture of nanorods and nanowires are grown upon same glass substrates. • The grown nanostructures are found to be vertically aligned. • Improved electron carrier concentration is observed. • Luminescence properties of these ZnO nanostructures are highly enhanced