Quantum transport devices application in multi-walled carbon-nano-tubes

Recently, there are many interests on electronics nano-device applications based on carbon nano-tubes (CNT). We have studied the low temperature transport properties due to the crossing of two multi walled carbon nano-tubes (MWNTs). Especially, there exists a peak structure in the zero bias anomalies of the I-V characteristics of the crossing and this is found to be very sensitive to change of temperature, magnetic field and source drain voltage. Fano resonance like behavior has been observed in the central structure of the zero bias anomaly.[1,2] With radio wave irradiations in the microwave-region, the central part of the anomaly is found to respond strongly. It can be connected to new CNT applications for extremely small sized microwave detection. Also, we have observed quantum coherent transport in MWNT and hybrid devices using MWNT and single walled carbon nano-tube (SWNT). In such nano-scaled electronic devices, there exist crossing points as a quantum dot or quantum point contact. The origin of the sensitivity in the crossing may be associated with the quantum nature in the transport through localized or conductive states in the CNT However, such sensitiveness is unstable, it may also be sensitive to the thermal cycling in the low temperature transport measurements. Since it must be originated to the nano-scaled structure changes in CNT, we must carefully clarify on the nature of the structural defects in the CNT In the quantum device applications, such as microwave detection and so on, it should be noted that there exist certain degradations preventing the coherent properties in low temperature transports which is strongly related to the device performance. The details of the results of recent experiments in MWNT and SWNT, will be discussed based on quantum transport device performances.