Activation Energy for Hopping Conduction

Author(s):  
Boris I. Shklovskii ◽  
Alex L. Efros
1999 ◽  
Vol 572 ◽  
Author(s):  
A. O. Evwaraye ◽  
S. R. Smith ◽  
W. C. Mitchel

ABSTRACTThermal admittance spectroscopy was used to characterize the shallow dopants in chemical vapor deposition ( CVD) grown thin films and in sublimation sandwich method ( SSM) grown 4H-SiC layers. The values of the activation energy levels of EC − 0.054 eV for Nitrogen at the hexagonal site and of EC − 0.10 eV for Nitrogen at the cubic site were indices of comparison. The net carrier concentrations ( ND − NV ) of the films were determined by capacitance-voltage measurements. The net carrier concentrations for the SSM films ranged from 2 × 1017 to 7 × 1017 cm−3. The two Nitrogen levels were observed in the CVD films. Hopping conduction with an activation energy of EC −0.0058 eV was observed in one SSM sample having ND − NV = 7 × 1017 cm−3.


1994 ◽  
Vol 08 (23) ◽  
pp. 1453-1459
Author(s):  
M.Y. NADEEM

The frequency and temperature dependence of the ac conductance and the capacitance are studied in the frequency range of 1 to 20 kHz for the coevaporated GeO 2/ BaO thin layers sandwiched between Al metallic electrodes. The measurements are undertaken to establish the low temperature conduction in these diode structures as the electronic hopping conduction. The activation energy involved in this mechanism is evaluated.


1977 ◽  
Vol 55 (17) ◽  
pp. 1512-1517 ◽  
Author(s):  
P. K. Lim ◽  
D. E. Brodie

This paper describes the preparation of mature amorphous ZnSe, obtained in thin film form by vapor deposition of the ZnSe compound. Room temperature resistivities of annealed a-ZnSe samples are ~1013 Ω cm. The material is n-type and the dc conductivity is consistent with a hopping conduction mechanism at temperatures up to the rapid crystallization temperatures which occur around 180 °C and higher. The activation energy for hopping at the band edge is 0.9 ± 0.05 eV and it is 0.09 ± 0.02 eV for hopping at the Fermi level, Ef.Variable range hopping occurs at Ef, below 270 K, and the density of states N(Ef) at Ef is of the order of 1017 (cm3 eV)−1. Annealing a-ZnSe prior to obtaining fully matured samples reduces N(Ef).


1973 ◽  
Vol 51 (15) ◽  
pp. 1593-1596 ◽  
Author(s):  
J. B. Webb ◽  
D. E. Brodie

The frequency dependence of conductivity in mature films of amorphous ZnTe (a-ZnTe) is found to be consistent with the hopping type conduction model proposed by Jonscher with a quadratic sequence of firing times. The frequency dependent part of the conductivity obeys a power law relation of the form [Formula: see text] where "n" takes the value of 0.50 ± 0.01 in the temperature range 167 K < T < 300 K, whereas the real part of the relative permittivity follows an ωn−1 dependence. Effects due to dipole relaxation are also observed and can mask the hopping conduction observed. No well-defined single activation energy is observed for the conductivity over the temperature range studied.


JETP Letters ◽  
2000 ◽  
Vol 71 (1) ◽  
pp. 17-20 ◽  
Author(s):  
A. P. Mel’nikov ◽  
Yu. A. Gurvich ◽  
L. N. Shestakov ◽  
E. M. Gershenzon

2013 ◽  
Vol 102 (13) ◽  
pp. 133503 ◽  
Author(s):  
Kai-Huang Chen ◽  
Rui Zhang ◽  
Ting-Chang Chang ◽  
Tsung-Ming Tsai ◽  
Kuan-Chang Chang ◽  
...  

1998 ◽  
Vol 510 ◽  
Author(s):  
A. O. Evwaraye ◽  
S. R. Smith ◽  
W. C. Mitchel

AbstractThermal admittance spectroscopy has been used to study the thermal activation energy of nitrogen at the hexagonal and cubic sites in 4H-SiC as function of net doping concentration. The net doping concentration- of te samples, which was determined from 1/C2 vs. V plots, ranges from 1.5 × 1014 cm−3 to 4 × 1018 cm−3. The thermal activation energy of nitrogen was determined to be Ee O.054 eV and Ee O.101 eV for nitrogen at hexagonal and cubic sites respectively for ND - NA ≤ 1016 cm−3. As the free carrier concentration increases from 1016 cm−3 to 1.0 × 1018 cm3, the thermal activation energy of nitrogen at the hexagonal site decreases from 54 meV to 24 meV. At ND - NA ≥1.0 × 10 cm−3 hopping conduction is the only conduction mechanism and has an activation energy of 3-9 meV.


2003 ◽  
Vol 762 ◽  
Author(s):  
A. Gordijn ◽  
J.K. Rath ◽  
R.E.I. Schropp

AbstractDue to the high temperatures used for high deposition rate microcrystalline (μc-Si:H) and polycrystalline silicon, there is a need for compact and temperature-stable doped layers. In this study we report on films grown by the layer-by-layer method (LbL) using VHF PECVD. Growth of an amorphous silicon layer is alternated by a hydrogen plasma treatment. In LbL, the surface reactions are separated time-wise from the nucleation in the bulk. We observed that it is possible to incorporate dopant atoms in the layer, without disturbing the nucleation. Even at high substrate temperatures (up to 400°C) doped layers can be made microcrystalline. At these temperatures, in the continuous wave case, crystallinity is hindered, which is generally attributed to the out-diffusion of hydrogen from the surface and the presence of impurities (dopants).We observe that the parameter window for the treatment time for p-layers is smaller compared to n-layers. Moreover we observe that for high temperatures, the nucleation of p-layers is more adversely affected than for n-layers. Thin, doped layers have been structurally, optically and electrically characterized. The best n-layer made at 400°C, with a thickness of only 31 nm, had an activation energy of 0.056 eV and a dark conductivity of 2.7 S/cm, while the best p-layer made at 350°C, with a thickness of 29 nm, had an activation energy of 0.11 V and a dark conductivity of 0.1 S/cm. The suitability of these high temperature n-layers has been demonstrated in an n-i-p microcrystalline silicon solar cell with an unoptimized μc-Si:H i-layer deposited at 250°C and without buffer. The Voc of the cell is 0.48 V and the fill factor is 70 %.


Diabetes ◽  
2018 ◽  
Vol 67 (Supplement 1) ◽  
pp. 1897-P
Author(s):  
HISASHI YOKOMIZO ◽  
ATSUSHI ISHIKADO ◽  
TAKANORI SHINJO ◽  
KYOUNGMIN PARK ◽  
YASUTAKA MAEDA ◽  
...  

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