Temperature Dependence of 1/f Noise and Electrical Conductivity Measurements on p-type a-Si:H Devices

2013 ◽  
Vol 1536 ◽  
pp. 181-186 ◽  
Author(s):  
V. C. Lopes ◽  
E. Hanson ◽  
D. Whitfield ◽  
K. Shrestha ◽  
C. L. Littler ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Temperature Dependence ◽  
Valence Band ◽  
Hole Mobility ◽  
Type A ◽  
Localized States ◽  
Conductivity Measurements ◽  
Band Tail ◽  
Resistance Change ◽  
P Type

ABSTRACTNoise and electrical conductivity measurements were made at temperatures ranging from approximately 270°K to 320°K on devices fabricated on as grown Boron doped p-type a-Si:H films. The room temperature 1/f noise was found to be proportional to the bias voltage and inversely proportional to the square root of the device area. As a result, the 1/f noise can be described by Hooge’s empirical expression [1]. The 1/f noise was found to be independent of temperature in the range investigated even though the device conductivity changed by a factor of approximately 4 over this range. Conductivity temperature measurements exhibit a T-0.25 dependence, indicative of conduction via localized states in the valence band tail [2,3]. In addition, multiple authors have analyzed hole mobility in a-Si:H and find that the hole mobility depends on the scattering of mobile holes by localized states in the valence band tail [4-7]. We conclude that the a-Si:H carrier concentration does not change appreciably with temperature, and thus, the resistance change in this temperature range is due to the temperature dependence of the hole mobility. Our results are applicable to a basic understanding of noise and conductivity requirements for a-Si:H materials used for microbolometer ambient temperature infrared detection.

scholarly journals Resistivity and Carrier Mobility of the SmBa2 Cu3 O6+x Superconductor with Different Oxygen Doping Levels

1999 ◽  
Vol 54 (2) ◽  
pp. 95-100 ◽  
Author(s):  
G. Spinolo ◽  
P. Ghigna ◽  
G. Chiodelli ◽  
M. Ferretti ◽  
G. Flor
Keyword(s):  
High Temperature ◽  
Temperature Dependence ◽  
Oxygen Pressure ◽  
Anderson Localization ◽  
Carrier Mobility ◽  
Hole Mobility ◽  
Dc Conductivity ◽  
Sudden Increase ◽  
Conductivity Measurements ◽  
Oxygen Doping

Abstract DC conductivity measurements between 15 and 300 K are reported for SmBa2 Cu3O6+x samples with different oxygen doping amounts (x) produced by annealing under appropriate high temperature and oxygen pressure conditions and quenching. Samples with x≥0.5 are superconductors: Tc ~60 K at x=0.7, Tc >80 K at ; x=0.9. The transition from superconduction to non-superconduction corresponds to the tetragonal to orthorhombic structural tran-sition and to the transition from semiconducting to metallic temperature dependence of the resistivity. Oxygen doping causes a sudden increase of hole mobility near x=0.5. Below this threshold, the be-havior of the carrier mobility is in agreement with an Anderson localization.

Vicrostructure and Electrical Properties of Kevlar/Polypyrrole Composite Fibers

1989 ◽  
Vol 175 ◽  
Author(s):  
L. P. Rector ◽  
D. DeGroot ◽  
T. J. Marks ◽  
S. H. Carr
Keyword(s):  
Electrical Conductivity ◽  
Temperature Dependence ◽  
Transport Model ◽  
Temperature Limit ◽  
Hybrid Fibers ◽  
Electrically Conducting ◽  
High Temperature Limit ◽  
Uniform Dispersion ◽  
Polypyrrole Composite ◽  
P Type

AbstractElectrically conducting composite polypyrrole/poly(p-phenyleneterephthalamide) (PPTA or KEVLAR) fibers have been prepared by chemical polymerization of pyrrole within the interstices of the hydrogen-bonded gel structure of never-dried PPTA fibers. The resultant fibers contain a uniform dispersion of polypyrrole, as evidenced by scanning electron microscopy. The temperature dependence of the electrical conductivity of these hybrid fibers is presented. The conductivity is well described by the fluctuation-induced charge transport model over the entire temperature range of interest. However, the low temperature electrical conductivity also exhibits a hoppinglike temperature dependence, and an Arrhenius-like temperature dependence is observed in the high temperature limit. Measurements of the temperaturedependent tbermopower are indicative of a p-type carrier.

Boron doping in a-SiO:H,

2014 ◽  
Vol 92 (7/8) ◽  
pp. 586-588 ◽  
Author(s):  
Y. Kitani ◽  
T. Maeda ◽  
S. Kakimoto ◽  
K. Tanaka ◽  
R. Okumoto ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Hole Mobility ◽  
Boron Doping ◽  
Type A ◽  
Dark Conductivity ◽  
Wide Range ◽  
P Type ◽  
Hydrogenated Amorphous ◽  
Silicon Oxygen

Boron-doping characteristics in hydrogenated amorphous silicon–oxygen alloys (a-SiO:H) have been studied in contrast to those in hydrogenated amorphous silicon (a-Si:H). Although the boron-incorporation efficiency shows almost the same value between a-SiO:H and a-Si:H, p-type a-SiO:H (p-a-SiO:H) exhibits lower dark conductivity by one or two orders of magnitude as compared to p-type a-Si:H (p-a-Si:H) in a wide range of doping levels. We have found that p-a-SiO:H exhibits low dark conductivity as compared to p-a-Si:H even when we choose samples showing the same activation energy from a variety of as-deposited and thermally annealed samples. We have concluded from the different Urbach-energy values between high quality intrinsic a-SiO:H and a-Si:H that the origin of low dark conductivity in p-a-SiO:H is due to low hole mobility.

Temperature Dependence of the Photoconductivity in p-Type a—Si:H

1991 ◽  
Vol 168 (1) ◽  
pp. K19-K21 ◽  
Author(s):  
A. G. Kazanskii ◽  
S. V. Kuznetsov
Keyword(s):  
Temperature Dependence ◽  
Type A ◽  
P Type

Effects of Processing on Structural Defects in Silicon

1984 ◽  
Vol 36 ◽  
Author(s):  
L. J. Cheng
Keyword(s):  
Temperature Dependence ◽  
Band Gap ◽  
Valence Band ◽  
Polycrystalline Silicon ◽  
Energy Levels ◽  
Structural Defects ◽  
Significant Shift ◽  
Twin Boundaries ◽  
Phosphorus Diffusion ◽  
P Type

ABSTRACTIt is found that the recombination activities of dislocation complexes and structural defects decorating twin boundaries in as-grown, p-type cast polycrystalline silicon have no observable temperature dependence in the range of 100–300 K, but the activities of these defects in phosphorusdiffused samples decrease with the increase of temperature in the same range. The results suggest that the phosphorus diffusion can cause a significant shift of energy levels of these defects toward the valence band from the middle of the band gap.

Thickness Effects on the Activation Energy of Source-Drain Current in P and N Channel Polycrystalline Silicon Thin Film Transistors

1990 ◽  
Vol 182 ◽  
Author(s):  
Babar A. Khan ◽  
Ranjana Pandya
Keyword(s):  
Thin Film ◽  
Activation Energy ◽  
Thin Film Transistors ◽  
Drain Current ◽  
Localized States ◽  
Subthreshold Slope ◽  
Band Tail ◽  
Silicon Thin Film ◽  
Sharp Drop ◽  
P Type

AbstractWe report activation energy measurements of the source-drain current of polysilicon thin film transistors (TFTs). We have shown earlier that measurements carried out on unhydrogenated TFTs can be explained by the presence of band tail states in addition to deep localized states. After hydrogenation, the density of band tail states is greatly reduced and the data can be fitted with only the deep states.In the present work we have studied both n and p channel TFTs. This was done by measuring both type of devices on the same wafer so that differences due to processing conditions could be ruled out. Both type of devices had intentionally undoped channels and were identical except for the n or p type source-drain regions. The thinner TFTs discussed in this work have a sharper drop in the activation energy than would be expected from idealized calculations. This sharp drop in activation energy is also an indication of a sharp subthreshold slope. This decrease in subthreshold slope (Volts/decade) is due to the complete depletion of the channel polysilicon, which leads to a rapid increase (or decrease) in the surface potential as a function of the gate voltage.

A study by electrical conductivity measurements of the semiconductive and redox properties of Nb-doped NiO catalysts in correlation with the oxidative dehydrogenation of ethane

2015 ◽  
Vol 17 (12) ◽  
pp. 8138-8147 ◽  
Author(s):  
Ionel Popescu ◽  
Zinovia Skoufa ◽  
Eleni Heracleous ◽  
Angeliki Lemonidou ◽  
Ioan-Cezar Marcu
Keyword(s):  
Electrical Conductivity ◽  
Oxidative Dehydrogenation ◽  
Redox Properties ◽  
Conductivity Measurements ◽  
Oxidative Dehydrogenation Of Ethane ◽  
P Type

All the catalysts were partially reduced during catalysis and the ODH selectivity was inversely correlated with their p-type semiconductivity under the reaction mixture.

Electrical Conductivity and Nonstoichiometry in Pr0.545Ce0.455O2-x

1996 ◽  
Vol 453 ◽  
Author(s):  
O. Porat ◽  
H. L. Tuller ◽  
M. Shelef ◽  
E. M. Logothetis
Keyword(s):  
Electrical Conductivity ◽  
Phase Separation ◽  
Solid State ◽  
Small Polaron ◽  
Coulometric Titration ◽  
Oxygen Nonstoichiometry ◽  
Conductivity Measurements ◽  
Two Phase ◽  
Polaron Hopping ◽  
P Type

AbstractThe oxygen nonstoichiometry of Pr0.545Ce0.455O2-x was studied by solid state coulometric titration and was found to be extensive (0 ≤ y ≤ 0.28) at temperatures of 400–600 °C. The Po2 - x curves showed evidence of the existence of a number of single and two phase regions. Electrical conductivity measurements, performed under similar conditions, exhibited a p-n transition for temperature of 500 °C and below. The activated p-type conductivity was modeled in terms of the small polaron hopping mechanism. The p-n transition was correlated with the onset of phase separation.

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