ABSTRACT
This chapter gives an overview of nanocomposite organic electron beam (EB) resist polymers from the viewpoint of advanced technology for biology and medicine. One of the serious remaining issues with organic devices is difficulty in simultaneous control of lateral size and position of their structures at nanometer scales. The problem can be solved if organic EB resists themselves are made electrically conductive and are used for the constituent materials of main nanoscale electronic devices. Therefore, here, we propose organic molecule-containing electrically conductive EB resists and discuss their applicability to biosensors with high functionality. First, the nanocomposite EB organic resist of ZEP520A containing [6,6]-phenyl-C61 butyric acid methyl ester (PCBM) is described. Capacitance-voltage (C-V) characteristics for the fabricated capacitors of the nanocomposite resist layer showed an excellent memory effect, which indicates the electrical conductivity of the proposed nanocomposite material. Structures of the material having line and dot patterns with sizes less than 200 nm were successfully fabricated by using an extremely simple process with only EB exposure and development. Semispherical PCBM aggregations whose base diameters and base center-to-center distance between adjacent aggregations are about 60 and 80 nm were observed in the nanocomposite resist. Next, descriptions are given for the nanocomposite EB organic resist of ZEP520A containing 8-hydroxyquinoline aluminum (Alq3). After the simple process with EB exposure and development for the nanocomposite resist, square pattern structures somewhat less than 1.0 µm in lateral length were clearly formed. Greenlight emissions were observed from the electroluminescence (EL) devices with the nanocomposite resist. Biosensors with light-emitting nanowire channels of ZEP520A containing Alq3 have the ability to estimate the precise number and position of biomolecules attached near the channel. These results open the door to the simple fabrication of densely integrated highly sensitive and functional biosensors with electrically conductive nanostructures for multiplexed and simultaneous diagnoses.
