Nano-fluidic devices have great potential in the applications of biology, chemistry, and medicine. However, their applications have been hampered by their expensive or complicated fabrication methods. We present a new and simple approach to fabricate low-cost two-dimensional (2D) nano-mold based on ultraviolet (UV) lithography and wet etching. The influence of UV lithography parameters on the width dimension of AZ5214 photoresist was investigated. With the optimized parameters of UV lithography, the width dimension of photoresist patterns had sharply decreased from microscale to nano-scale. At the same time, the influences of etching time on the over-etching amount of SiO2 film and nano-mold depth were also analyzed for further reducing the width of nano-mold. In addition, the effect of photoresist mesas deformation on the nano-mold fabrication was also studied for improving the quality of nano-mold. By the proposed method, trapezoid cross-sectional 2D nano-mold with different dimensions can be obtained for supporting varied applications. The minimum nano-mold arrays we fabricated are the ones with the dimensions of 115[Formula: see text]nm in top edge, 284[Formula: see text]nm in bottom edge, and 136[Formula: see text]nm in depth. This method provides a low-cost way to fabricate high-quality and high-throughput 2D nano-mold.

Silicone oil is a type of fluid with low viscosity, but it is not easy to form stable cone jet for electrohydrodynamic printing. In this paper, we proposed a new electrohydrodynamic printing method for patterns fabrication with this kind of low viscosity fluid. Dots array was first printed on the substrate at higher direct current voltage. Then by controlling the moving speed of the platform, the dots were connected into lines according to the fluidity of the silicone oil and its low surface tension. With the proposed method, the patterns with silicone oil can be successfully formed by electrohydrodynamic printing. In the experiment, the influence of main parameters including applied voltage, moving speed of substrate, distance from needle to substrate, and axial length of droplet on the quality of printed lines was studied. Finally, by optimizing the printing parameters, the silicone oil lines with width of 73 µm and low surface roughness were printed.

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The fabrication of inexpensive nano-gaps is vitally important for the research and application of nanochannel-based devices. This study presents a low-cost and simple method for the fabrication of nano-gaps using thermal evaporation and stripping techniques. The structural morphology of metal films deposited on the convex structures of photoresist by sputtering and thermal evaporation was studied. The effect of angles of thermal evaporation on the width of nano-gaps was investigated. The characteristics of metal film deposited on the convex structures of photoresist and spaces between these convex structures after stripping were investigated, and the adhesive force between the metal film and silicon substrate was also analyzed. Finally, a metal film of Cu was deposited on the convex structures of photoresist by thermal evaporation. After stripping, nano-gaps with a width of 187 nm were fabricated. The method proposed in this paper can be employed to mass-produce two-dimensional nanochannels based devices at low cost.

Nanofluidic devices with two-dimensional nanochannels have many applications in biology and chemistry, however, it is still a challenge to develop a low-cost and simple method for fabricating nano-masks that can be used to produce two-dimensional nanochannels. In this paper, a novel low-cost and simple method, based on UV lithography and oxygen plasma, was proposed to fabricate nano-mask. The influence of exposure time on the photoresist mesas was investigated in the ultraviolet lithography process. The parameters of RF power and treatment time on the width reduction of photoresist mesas were analyzed by the oxygen plasma. In our work, in order to increase the efficiency controllability of photoresist removal, a RF power of 90 W, a pressure of oxygen plasma 60 Pa, and the time division method were adopted to remove photoresist by oxygen plasma. Finally, nano-patterns of photoresist mesas with bottom width of 330 nm were successfully fabricated. The proposed method provides a low-cost way to produce high-throughput two-dimensional nanochannels.