SYNTHESIS, MECHANICAL AND ELECTRICAL PROPERTIES OF CARBON MICROCOILS AND NANOCOILS

2010 ◽  
Vol 03 (04) ◽  
pp. 263-267 ◽  
Author(s):  
HUI BI ◽  
KAICHANG KOU ◽  
YONGBAI YIN ◽  
KOSTYA (KEN) OSTRIKOV ◽  
ZONGWEN LIU

The results on the synthesis, mechanical and electrical properties of carbon microcoils and nanocoils (CMCs, CNCs) synthesized using catalytic CVD and Ni–P and Co–P catalyst alloys, respectively, are reported. SEM analysis reveals that the CMCs and CNCs have unique helical morphologies, and diameters of 5.0–9.0 μm and 450–550 nm, respectively. Moreover, CMCs with flat cross-section can be stretched to 3 times their original coil lengths. Current–voltage characteristics of a single microcoil have also been obtained. It is found that the CMCs have the electrical conductivity between 100 and 160 S/cm, whereas the electrical resistance increases by about 20% during the coil extension. Besides, the microcoils can produce light in vacuum when the test voltage reaches 10 V. The emission intensity increases as the voltage increases. The mechanical and electrical properties of CMCs and CNC make them potentially useful in many applications in micromagnetic sensors, mechanical microsprings and optoelectronics.

2016 ◽  
Vol 674 ◽  
pp. 109-114 ◽  
Author(s):  
Jan Pospisil ◽  
Veronika Schmiedova ◽  
Oldrich Zmeskal ◽  
Viliam Vretenar ◽  
Peter Kotrusz

The paper deals with the study of optical and electrical properties of inkjet-printed graphene oxide (GO) layers, which can be used e.g. for the preparation of various types of electronic devices. To ensure stable inkjet printing conditions of GO solution, mixture was thoroughly stirred for 1 h at room temperature or sonicated in the bath for 30 min. The thicknesses of prepared layers were determined by spectroscopic ellipsometry and profilometry. An electrical conductivity of GO was increased by the multistep reduction (due to annealing) – the conductivity was changed by these processes about seven orders of magnitude (GO is an isolator and reduced GO is a conductor). For electrical and dielectric measurements, samples with GO and mixture of GO with PEDOT were prepared. All current-voltage characteristics have a diode character. From AC measurements the bulk electrical conductivity and geometric capacity of prepared layers were determined.


Author(s):  
Sergey Gango ◽  
Konstantin Gusev ◽  
Evgeniy Ilin ◽  
Mikhail Predtechensky ◽  
Vladimir Solovyev ◽  
...  

Experimental study of single-wall carbon nabotubes (CNT) effect on the electrical properties of polymeric composite materials based on epoxy matrix has been carried out. Direct-current (DC) as well as alternating-current (AC) electrical conductivity of nanocomposites with different CNT concentrations have been investigated in the temperature interval from 293 K to 373 K. Measurements of Seebeck coefficient confirm n-type conductivity of composite with CNTs. Percolation threshold of the composite material under study has been estimated. It has been found that addition of single-wall CNT at low concentration causes hysteresis of current-voltage characteristics and the temperature dependences of electrical conductivity as well as its anisotropy in the samples under study. No noticeable frequency dependence of the AC electrical conductivity has been found in the frequency range from 100 Hz to 300 kHz.


1998 ◽  
Vol 258-263 ◽  
pp. 1848-1855 ◽  
Author(s):  
K Shiiyama ◽  
M.M.R Howlader ◽  
S.J Zinkle ◽  
T Shikama ◽  
M Kutsuwada ◽  
...  

2019 ◽  
Vol 43 (41) ◽  
pp. 16255-16263
Author(s):  
Mrinmoy Ghosh ◽  
Sandip Saha ◽  
Abhijit Banerjee ◽  
Dieter Schollmeyer ◽  
Ananda Sarkar ◽  
...  

The structure, FESEM, Al/complex/ITO microstructure and the current–voltage characteristics of the copper(ii) azido bridged dimer.


2016 ◽  
Vol 11 (4) ◽  
pp. 155892501601100 ◽  
Author(s):  
Wei Liu ◽  
Fujun Xu ◽  
Nianhua Zhu ◽  
Shuang Wang

Carbon nano tube (CNT) yarn is an axially aligned CNT assembly. It has great potential many applications. In this study, the mechanical and electrical properties of the aerogel-spun CNT yarns and CNT/Polydimethylsiloxane (PDMS) composite yarns were investigated. The CNT/PDMS yarn was fabricated by droplet infiltration of PDMS solution into the aerogel-spun CNT yarn. The mechanical properties of the CNT/PDMS yarns were significantly improved with an average strength of 837.29 MPa and modulus of 3.66 GPa, over 100% improvement compared to the original CNT yarns. The electrical conductivity of the CNT/PDMS yarn increased from 1636 S/cm to 3555 S/cm. The electromechanical properties of CNT/PDMS yarns demonstrated that such CNT yarn could be suitable for strain sensors.


2013 ◽  
Vol 591 ◽  
pp. 54-60
Author(s):  
Xiu Li Fu ◽  
Yan Xu Zang ◽  
Zhi Jian Peng

The effect of WO3doping on microstructural and electrical properties of ZnO-Pr6O11based varistor materials was investigated. The doped WO3plays a role of inhibitor in ZnO grain growth, resulting in decreased average grain size from 2.68 to 1.68 μm with increasing doping level of WO3from 0 to 0.5 mol%. When the doping level of WO3was lower than 0.05 mol%, the nonlinear current-voltage characteristics of the obtained varistors could be improved significantly with increasing amount of WO3doped. But when the doping level of WO3became higher, their nonlinear current-voltage performance would be dramatically deteriorated when more WO3was doped. The optimum nonlinear coefficient, varistor voltage, and leakage current of the samples were about 13.71, 710 V/mm and 13 μA/cm2, respectively, when the doping level of WO3was in the range from 0.03 to 0.05 mol%.


2011 ◽  
Vol 415-417 ◽  
pp. 1042-1045
Author(s):  
Wen Deng ◽  
Zhen Quan Lei ◽  
Jiao Ling Zhao ◽  
Yan Qiong Lu ◽  
Ding Kang Xiong

The effect of the Fe2O3dopant on the electronic densities and the electrical properties has been studied in a ZnO-Bi2O3-SnO2-Co2O3-MnO2-TiO2-Ni2O3-Fe2O3system by the measurements of positron lifetime spectra, coincidence Doppler broadening spectra and current-voltage characteristics. The results show that the 3d electron signal in the spectrum of the varistor increases with the Fe2O3content. The addition of small amount of Fe2O3into the ZnO-based varistor leads to an increase in the donor concentration in the bulk and the defects in the varistor. As the Fe2O3content increased, the threshold voltage (VT) and the nonlinear coefficient (α) of the varistor decreased monotonously.


1995 ◽  
Vol 378 ◽  
Author(s):  
Hisayoshi Fujikawa ◽  
Yasunori Taga

AbstractTa2O5-based composite films prepared by magnetron sputtering have been investigated with respect to their dielectric properties. As additive third oxides, Y2O3 and WO3 were found to be effective in improving insulating properties without decreasing their dielectric constant. Furthermore, electrical properties of Ta2O5-Y2O3 films were investigated by measuring the current-voltage characteristics in the temperature range from 100 to 330 K. Measurement of temperature dependence of the leakage current revealed that the conduction mechanism at RT changed from the Poole-Frenkel type to the Fowler-Nordheim tunneling type by adding Y2O3 into Ta2O5. Based on the detailed analysis of the results, it is concluded that the addition of Y2O3 into the Ta2O5 film is effective in the reduction of defect density without high-temperature annealing and the alteration of electrical conduction mechanisms of the films.


Sign in / Sign up

Export Citation Format

Share Document