RESUMO
A 3D ITO nanowire network with high quality by using polystyrene as an assisted material has been prepared, demonstrating superior optoelectronic performances with a sheet resistance of 193 Ω/sq at 96% transmission. Both remarkable flexibility tested under bending stress and excellent adhesion applied on special terrain substrate have been achieved. This method has led to a full coverage of micro-holes at a depth of 18 µm and a bottom spacing of only 1 µm, as well as a perfect gap-free coverage for micro-tubes and pyramid array. It has been proved that this 3D ITO nanowire network can be used as a transparent conductive layer for optoelectronic devices with any topography surface. Through the application on the micro-holes, -tubes and -pyramid array, some new characteristics of the 3D ITO nanowires in solar cells, sensors, micro-lasers and flexible LEDs have been found. Such 3D ITO nanowire networks could be fabricated directly on micro-irregular substrates, which will greatly promote the application of the heterotypic devices.
RESUMO
ITO nanowires have been successfully fabricated using a radio-frequency sputtering technique with a high RF-power of 250W. The fabrication of the ITO nanowires has been optimized through the study of oxygen flow rates, temperatures and RF-power. The difference in the morphology of the ITO nanowires prepared by using a new target and a used target has been first observed and the mechanism for the difference has been discussed in detail. A hollow structure and air voids within the nanowires are formed during the process of the nanowire growth. The ITO nanowires fabricated by this method has demonstrated good conductivity (15Ω/sq) and a transmittance of more than 64% at a wavelength longer than 550nm after annealing. Furthermore, detailed microstructure studies show that the ITO nanowires exhibit a large number of oxygen vacancies. As a result, it is expected that they can be useful for the fabrication of gas sensor devices.