Direct formation of ZnO nanostructures by chemical solution deposition and EUV exposure

The development of effective methods for the fabrication of ZnO nanostructures is important for the use of this semiconductor material with interesting optical and electronic properties. Chemical solution deposition methods have been demonstrated for creating ZnO films and electron beam exposure of a precursor film, zinc naphthenate, has been shown to yield ZnO nanostructures. Here, we report on the fabrication of ZnO nanostructures with photon beam exposure of a precursor film in the extreme ultraviolet range followed by a high temperature anneal in air. Interference lithography at this wavelength (13.5 nm) led to the production of extremely smooth line/space and dot array type periodic nanostructures with sizes as small as 10 nm. ZnO films obtained through EUV exposure exhibit markedly improved PL spectra with a sharp emission line in the UV range and much suppressed green emission. Electron microscopy and x-ray diffraction measurements also show strong effects of the EUV exposure step in ZnO formation as a function of precursor film thickness, EUV exposure dose and anneal temperature. The use of energetic photons for direct formation of ZnO nanostructures is found to be a method that warrants more investigation for the fabrication of patterned ZnO films with controlled properties.