Abstract
High-density ordered triangular Si nanopillars with sharp tips and varied slopes were fabricated by reactive ion etching of ordered Ni nanodot arrays,patterned with nanosphere lithography, on silicon. The slope and aspect ratio of the nanopillars were controlled by the variation of the mixing ratio of CF4 and O2 in the etching gas. Excellent field emission properties are attributed to the well-controlled spacing between nanopillars so that the antenna effect is minimized. Sharp tips and flared base, which are advantageous for high field emission current and mechanical/thermal stability, respectively, can be tailor-made depending on the applications. Large–area nanoporous ZnO arrays were prepared on the Si substrate. The diameters of pores are varied with the size of the nanospheres. The porous structure has a high surface-volume ratio, and it can contribute to a high sensitivity UV photosensor. TEM grid was used to be a mask to fabricate the Ti/Au interdigitated electrode. The resistance decreased when the wavelength of the incident light is in the UV region. The value of Imax/Idark is higher with the reduction of pore diameter. The maximum value is as high as 250. The use of nanoporous ZnO as photosensor is of low cost and has high sensitivity compared to the ZnO film. Well aligned AlN nanotips are fabricated by reactive ion etching the c-plane AlN thin film on the sapphire with etching gases of Cl2 and BCl3. The etching parameters, such as etching time, pressure and RF power, affect the height and morphology of AlN nanotips. Well aligned and tall AlN nanotips with small apex are obtained by the RIE etching via an appropriated etching recipe. The field-emission properties of nanotips were measured. In addition, well aligned AlN nanocolunm with bundled nanotips array are produced by etching the patterned AlN thin film with SiO2 nanospheres (700nm).