A low temperature combination method for the production of ZnO nanowires

The growth of large-area, patterned and oriented ZnO nanowires on silicon using a low temperature silicon-CMOS compatible process is demonstrated. Nanowire synthesis takes place using a thin nucleation layer of ZnO deposited by radiofrequency magnetron sputtering, followed by a hydrothermal growth step. No metal catalysts are used in the growth process. The ZnO nanowires have a wurtzite structure, grow along the c-axis direction and are distributed on the silicon substrate according to the pre-patterned nucleation layer. Room temperature PL measurements of the as-grown nanowires exhibit strong yellow-red emission under 325 nm excitation that is replaced by ultraviolet emission after annealing. This method can be used to integrate patterned ID nanostructures in optoelectronic and sensing applications on standard silicon CMOS wafers.