Research
Research Areas
New Printing Technology:
Electro-hydrodynamic Nanowire/Nozzle Printing (ENP)
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Nanowire Printing
Nozzle printing technology has been usually used for adhesive patterning to encapsulate electronic devices with a glass lid. Nozzle printing provides the line pattern of liquid phase solution. Recently, nozzle printing in place of ink-jet printing becomes attractive due to the demonstrated high performance of produced OLED panels. Production of nanowiresor nanofibers by nozzle printing is a great challenge to fabricate large-array electronic devices. When the high voltage is applied to the nozzle, the electric field between the tip and the grounded collector can stabilize and stretch the jet. We call this new printing technology as “Electro-hydrodynamic Nanowire/Nozzle Printing (ENP)”.
Highly aligned PVK Nanowires
Large-area nanowire FETs array
We can fabricate highly-aligned organic nanowires array which had totally parallel orientation and regular spacing using the ENP system.
We can also fabricate the large-area nanowire devices array in very simple and fast.
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Organic Nanowire Lithography (ONWL)
We can apply ENP to form large-area nano-sized patterns. Using ONWL, well-aligned nano- gap metal patterns can be fabricated very quickly at a desired position. In the ONWL process,aligned PVK NWs fabricated using ENPare used as a shadow mask of deposited metal films. After printing PVK NWs on a substrate, followed by deposition of metal films, the ONWs are removed either by sonicatingthe solvent to dissolve them, or by using adhesive tapes to detach them. As the contact area between PVK NWs and substrate is minimal, and as the deposited metal film is thinner than the NW radius,resulting in no physical contact between the NW mask and deposited metal film, wires can be easily removed.
Using the ONWL, complicate nano-patterns can be fabricated on large-area simply. Here are the perpendicularly aligned NW patterns, and grid-structured gold nano-gap patterns over on an 8-inch wafer which were obtained after ONWL. ONWL can be also used to form the nano-channel devices.
Furthermore, ONWL can be also used to fabricate organic nano-gap pattern and nano-channel devices on flexible substrate. It means that ONWL is very applicable to fabricate the flexible nano- electronics. Therefore, ONWL is a potential alternative method to replace E-beam lithography, which has been usually used to fabricate the nano-patterns.
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