次世代ナノエレクトロニクスを志向した単層及び多層グラフェンナノリボンの電気特性に関する研究

Graphene nanoribbon (GNR) is a narrow strip of carbon atoms which has exceptional properties and are being exploited for various applications, such as in semiconductor electronics, solar cells, and sensors. However, the realization of GNR based devices still needs an extensive research to achieve the commercial specifications. This research is mainly emphasized on the synthesis of high-quality GNR from double-walled carbon nanotubes (DWNTs) and fabrication of field effect transistor (FET) devices. Moreover, the electrical transport properties were also investigated for single-layer GNR (sGNR), multi-layer GNR with and without adsorption of molecular nanoparticles. The electrical transport properties of GNR device was tuned to semiconducting with the adsorption of molecular nanoparticles. This study demonstrates a simple and fast approach to band gap formation in sGNR using Hexaazatriphenylenehexacarbonitrile (HAT-CN6). In this process, sGNRs were synthesized by unzipping of DWNTs followed by casting the solution of HAT-CN6. HAT-CN6 on GNR forms self-assembled nanoparticle and the adsorption of nanoparticles was confirmed by AFM observation. Further, the electric property of pristine sGNR device and the device with HAT-CN6 were measured using point-contact current imaging (PCI-) AFM and also with the FET device. Thus, the adsorbed nanoparticles on sGNR forms the electron trapping sites which result in a necklike structure of sGNR near the adsorbed region of the molecular nanoparticle. The neck region working similar to narrow width GNR (< 10 nm) allows the charge carriers passing through. Such a narrow sGNR has lateral confinement of charge carrier around the neck region hence the device turns to semiconducting. The activation energy of pristine sGNR and the sGNR with HAT-CN6 were calculated by the results of temperature change measurement as about 1.5 meV and 52 meV, respectively. The pristine sGNR has very low activation energy as compared to the device with HAT-CN6. Thus, the device with HAT-CN6 has a large transition from semimetallic to semiconducting property. The device could have various possible application in future electronics industry due to its semiconducting property. Moreover, the study also explains the fabrication of multi-layer GNR (mGNR) field effect transistor (FET) and control of its electrical property with the adsorption of the flat molecular nanoparticle. The stacked mGNR device shows the similar performance to the sGNR device due to lower inter layer coupling. Inter layer interaction was supposed to be lower since the turbostratic stacking of GNR was formed with CVD growth process. Next, HAT-CN6 were casted on the mGNR device to alter the electronic property of GNR. Thus, the adsorbed nanoparticles form the charge carrier trapping sites on mGNR and the channel width was narrowed due to the nanoparticles on GNR. Hence, the charge carriers are confined in a narrow channel and the device is in a transition state from semimetallic to semiconducting, which is similar to narrow width GNR. The on/off ratio and mobility of mGNR-FET device was also improved with the adsorption of the nanoparticle. The fabricated mGNR-FET device has wide area of semiconductor electronics applications in the semiconductor industry. Furthermore, X- and Y-type junctions were also fabricated using GNRs obtained by unzipping of DWNTs. The junction of the synthesized GNR shows semiconducting property whereas the other part shows the semimetallic property. The semiconducting property at the junction was supposed to be due to change in lattice orientation at the junction of two GNRs. Such a junction can have great interest for the device and wiring application in the semiconductor industry. The semiconducting property in the several X-type junctions of wide GNRs (greater than 10 nm) was investigated.九州工業大学博士学位論文 学位記番号：生工博甲第295号 学位授与年月日：平成29年6月30日1 Introduction|2 Methodology|3 Tuning the electrical property of single-layer graphene nanoribbon by adsorption of planar molecular nanoparticles|4 Fabrication of turbostratic multi-layer graphene nanoribbon field effect transistor and investigating the electrical property with the adsorption of HAT-CN666|5 Fabrication of X- and Y-type graphene nanoribbon cross junction and study the electrical transport property|6 Conclusion九州工業大学平成29年

次世代ナノエレクトロニクスを志向した単層および多層グラフェンナノリボンの電気特性に関する研究

九州工業大学博士学位論文（要旨）学位記番号：生工博甲第295号 学位授与年月日：平成29年6月30

Atomistic to circuit-level modeling of doped SWCNT for on-chip interconnects

In this article, we present a hierarchical model for doped single-wall carbon nanotube (SWCNT) for on-chip interconnect application. We study the realistic CVD grown SWCNT with defects and contacts, which induce important resistance values and worsens SWCNT on-chip interconnect performance. We investigate the fundamental physical mechanism of doping in SWCNT with the purpose of improving its electrical conductivity as well as combining mitigating the effects of defects and large contact resistance. The atomistic model provides insights on statistical variations of the number of conducting channels of doped SWCNT and SWCNT resistance variation with a various number of vacancy defects configurations. Based on atomistic simulations, we develop circuit-level models to simulate SWCNT interconnects and understand the impact of doping, defects, and contacts. Simulation results show an 80% resistance reduction by doping. Additionally, we observe that doping can mitigate the effects of defects and limited impact on contact resistance

Dispositif Capteur Piézorésistif à Module d'Amplification

Related patent: EP3557240A1;WO2019201958A1The present invention relates to a sensor device comprising a sensor module connected to an amplification module, said amplification module comprising at least one organic field effect transistor (FET) and amplifying a signal transmitted by said sensor module, wherein said sensor module and said amplification module are co-integrated on a same support. It also provides a sensor device wherein said sensor module is a piezoresistive sensor module which comprises at least one micropattern of a composite mixture layered on said support. The present invention also provides a process for preparing said sensor device, and an apparatus comprising at least one sensor device according to the invention.La présente invention concerne un dispositif capteur comprenant un module capteur connecté à un module d'amplification, ledit module d'amplification comprenant au moins un transistor à effet de champ (FET) organique et amplifiant un signal émis par ledit module capteur, ledit module capteur et ledit module d'amplification étant co-intégrés sur un même support. L'invention concerne également un dispositif capteur, ledit module capteur constituant un module capteur piézorésistif comprenant au moins un micromotif d'un mélange composite stratifié sur ledit support. La présente invention concerne également un procédé de préparation dudit dispositif capteur, ainsi qu'un appareil comprenant au moins un dispositif capteur selon l'invention

Biocapteur Piézoélectrique

Related patent: EP3556283A1;WO2019201956A1The present invention relates to a piezoelectric biosensor comprising carbon nanotubes (CNTs), optionally combined with an amplification system, to a process for preparing the same and to an apparatus comprising said piezoelectric biosensor, in particular a medical device usable for monitoring a body parameter. A piezoresistive biosensor according to the invention comprises at least one micropattern of a composite mixture layered on a flexible support, said composite mixture comprising at least a flexible biocompatible polymer and carbon nanotubes (CNTs) and said at least one micropattern having a continuous rectangular shape.La présente invention concerne un biocapteur piézoélectrique comprenant des nanotubes de carbone (CNT), éventuellement associés à un système d'amplification, un procédé de préparation de celui-ci et un appareil comprenant ledit biocapteur piézoélectrique, en particulier un dispositif médical utilisable pour surveiller un paramètre corporel. Un biocapteur piézorésistif selon l'invention comprend au moins une microstructure d'un mélange composite stratifié sur un support flexible, ledit mélange composite comprenant au moins un polymère biocompatible flexible et des nanotubes de carbone (CNT) et ladite ou lesdites microstructures ayant une forme rectangulaire continue

Electrochemical Glucose Sensor using Single-Wall Carbon Nanotube Field Effect Transistor

In this paper, we present a simple yet sensitive method for glucose sensing using carbon nanotube field-effect transistor (CNTFET) based biosensor. The CNTs were well-dispersed to form CNT networks and maintain functional connectivity among CNTs, which increases the electron transfer through the network and thus, the electronic readout. Moreover, glucose oxidase (GOx) molecules are immobilized by CNT functionalization to form effective and sensitive CNT networks as FET channel. The CNTs are functionalized with linkers (1-pyrenebutanoic acid succinimidyl ester) to immobilize GOx on CNTs, where GOx serves as a mediator between CNTs and glucose for electron transfer. The liquid analyte glucose is adsorbed on CNTs via GOx and linkers by releasing additional electrons in the CNTFET channel and thus, increasing the CNTFET readout current. The binding of the target glucose molecules and GOx emulates the gate potential of FET channel and the electronic response of the sensor is recorded in real-time. Moreover, the variations in electronic readout of CNTFET biosensor are observed and is stipulated due to variation in CNT dispersion on each device. Overall, this work presents a simple, fast, sensitive, low-cost, and low concentration (0.01 mM) detection of glucose using CNTFET sensors

Electrochemical Glucose Sensor using Single-Wall Carbon Nanotube Field Effect Transistor

In this paper, we present a simple yet sensitive method for glucose sensing using carbon nanotube field-effect transistor (CNTFET) based biosensor. The CNTs were well-dispersed to form CNT networks and maintain functional connectivity among CNTs, which increases the electron transfer through the network and thus, the electronic readout. Moreover, glucose oxidase (GOx) molecules are immobilized by CNT functionalization to form effective and sensitive CNT networks as FET channel. The CNTs are functionalized with linkers (1-pyrenebutanoic acid succinimidyl ester) to immobilize GOx on CNTs, where GOx serves as a mediator between CNTs and glucose for electron transfer. The liquid analyte glucose is adsorbed on CNTs via GOx and linkers by releasing additional electrons in the CNTFET channel and thus, increasing the CNTFET readout current. The binding of the target glucose molecules and GOx emulates the gate potential of FET channel and the electronic response of the sensor is recorded in real-time. Moreover, the variations in electronic readout of CNTFET biosensor are observed and is stipulated due to variation in CNT dispersion on each device. Overall, this work presents a simple, fast, sensitive, low-cost, and low concentration (0.01 mM) detection of glucose using CNTFET sensors