Electric field emission and anomalies of electrical conductivity above room temperature in heterogeneous NiO-SnO2 nano-ceramic composites

2020 ◽  
Vol 127 (3) ◽  
pp. 034102 ◽  
Author(s):  
S. Karmakar ◽  
Vanshree Parey ◽  
Chetan D. Mistari ◽  
Ranjit Thapa ◽  
M. A. More ◽  
...  
1977 ◽  
Vol 55 (3) ◽  
pp. 270-275 ◽  
Author(s):  
J. P. Crine ◽  
A. Friedmann ◽  
M. R. Wertheimer ◽  
A. Yelon

The electrical conductivity of various North American micas has been measured at room temperature for electric field strengths ranging from 102 to 5 × 104 V cm−1. It is shown that the conductivities observed are consistent with a percolation model in which Fe3+ provides the hopping centers.


The electrical conductivity produced by β -ray bombardment and by light irradiation in several diamonds was investigated in the temperature range 150 to 500° K. Considerable uniformity was observed in the behaviour of the specimens; all of them polarized strongly in the dark at room temperature, and polarization could be effectively eliminated by pulsing the electric field while maintaining the β -flux. Both the counting response and the photoconductivity increased as the temperature was lowered. This was interpreted as being largely due to an increase in the mobility of the charge carriers at lower temperatures, the quantitative relationship being consistent with Hall effect measurements. Accumulation of polarization was reduced by irradiation with red light or by elevation of temperature; at 420° K little sign of polarization remained. From various temperature effects, the thermal depths of the trapping levels in these diamonds were estimated at 0⋅6, 0⋅8 and 1 eV.


Author(s):  
W. P. Wergin ◽  
S. Roy ◽  
E. F. Erbe ◽  
C. A. Murphy ◽  
C. D. Pooley

Larvae of the nematode, Steinernema carpocapsae Weiser strain All, were cryofixed and freezesubstituted for 3 days in acetone containing 2% osmium tetroxide according to established procedures. Following chemical fixation, the nematodes were brought to room temperature, embedded in Spurr's medium and sectioned for observation with a Hitachi S-4100 field emission scanning electron microscope that was equipped with an Oxford CT 1500 Cryotrans System. Thin sections, about 80 nm thick, similar to those generally used in conventional transmission electron microscope (TEM) studies were mounted on copper grids and stained with uranyl acetate for 30 min and lead citrate for 5 min. Sections about 2 μm thick were also mounted and stained in a similar fashion. The grids were mounted on an Oxford grid holder, inserted into the microscope and onto a cryostage that was operated at ambient temperature. Thick and thin sections of the larvae were evaluated and photographed in the SEM at different accelerating voltages. Figs. 4 and 5 have undergone contrast conversion so that the images would resemble transmitted electron micrographs obtained with a TEM.


Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1518
Author(s):  
Minsu Kim ◽  
Dabin Park ◽  
Jooheon Kim

Herein, Sb2Se3 and β-Cu2Se nanowires are synthesized via hydrothermal reaction and water evaporation-induced self-assembly methods, respectively. The successful syntheses and morphologies of the Sb2Se3 and β-Cu2Se nanowires are confirmed via X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, field emission scanning electron microscopy (FE-SEM), and field emission transmission electron microscopy (FE-TEM). Sb2Se3 materials have low electrical conductivity which limits application to the thermoelectric generator. To improve the electrical conductivity of the Sb2Se3 and β-Cu2Se nanowires, polyaniline (PANI) is coated onto the surface and confirmed via Fourier-transform infrared spectroscopy (FT-IR), FE-TEM, and XPS analysis. After coating PANI, the electrical conductivities of Sb2Se3/β-Cu2Se/PANI composites were increased. The thermoelectric performance of the flexible Sb2Se3/β-Cu2Se/PANI films is then measured, and the 70%-Sb2Se3/30%-β-Cu2Se/PANI film is shown to provide the highest power factor of 181.61 μW/m·K2 at 473 K. In addition, a thermoelectric generator consisting of five legs of the 70%-Sb2Se3/30%-β-Cu2Se/PANI film is constructed and shown to provide an open-circuit voltage of 7.9 mV and an output power of 80.1 nW at ΔT = 30 K. This study demonstrates that the combination of inorganic thermoelectric materials and flexible polymers can generate power in wearable or portable devices.


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