10:30 〜 10:45
▼ [21a-231C-6] Electronic Noise Generation in Conductive Polymer/Metal Nanoparticle Molecular Network by Optical Stimulation
キーワード：noise generation, Au nanoparticle, self-doped polyaniline
In most cases, noise is regarded as an obstructer of signal processing. However, noise also plays a significant role in biological information processing system, including human brain. An example of the utility of noise is based on a phenomenon, stochastic resonance (SR), where a weak signal can be boosted to assure the signal transfer by adding white noise. We previously reported SR in DNA/Cytochrome C molecular network with external noise generator. For the realization of SR with molecular device, molecular noise generator is required.
In this work, we detected noise generation phenomena in SPAN-AuNP (self-doped polyaniline-gold nanoparticle) composite molecular network. SPAN serves as the conductive path of the network for its water solubility and high conductivity. AuNP (45 nm) is used as light absorber for its surface plasmonic properties. As the transport of conductive carrier will be modulated at the interface between SPAN and AuNP with light, a confinement of sample volume is also important in order to enhance the modulation. Figure 1(a) shows the overview of device and measurement method. Au/Cr electrodes are fabricated by thermal evaporation on SiO2/Si substrate, SPAN-AuNP lines were drawn between the gold electrodes by nanopipette (Figure 1(b)) using composite solution. The width and the length of the patterns are 3~10 µm and 500 µm, respectively. Electrical current was characterized by I/V amplifier using high-vacuum prober (10-4 Pa). Laser irradiation was preformed using a 0~20 mW tunable 532 nm laser source. As shown in Figure 2, we successfully detected noise generation phenomena with laser irradiation. The noise amplitude is approximately 10-3 times the current level and stable with time. Recently we found some evidence for the mechanism of noise generation, the details will be addressed at the presentation.
In this work, we detected noise generation phenomena in SPAN-AuNP (self-doped polyaniline-gold nanoparticle) composite molecular network. SPAN serves as the conductive path of the network for its water solubility and high conductivity. AuNP (45 nm) is used as light absorber for its surface plasmonic properties. As the transport of conductive carrier will be modulated at the interface between SPAN and AuNP with light, a confinement of sample volume is also important in order to enhance the modulation. Figure 1(a) shows the overview of device and measurement method. Au/Cr electrodes are fabricated by thermal evaporation on SiO2/Si substrate, SPAN-AuNP lines were drawn between the gold electrodes by nanopipette (Figure 1(b)) using composite solution. The width and the length of the patterns are 3~10 µm and 500 µm, respectively. Electrical current was characterized by I/V amplifier using high-vacuum prober (10-4 Pa). Laser irradiation was preformed using a 0~20 mW tunable 532 nm laser source. As shown in Figure 2, we successfully detected noise generation phenomena with laser irradiation. The noise amplitude is approximately 10-3 times the current level and stable with time. Recently we found some evidence for the mechanism of noise generation, the details will be addressed at the presentation.