Variable Temperature Measurement on Operating Pentacene-Based OTFT

2008 ◽  
Vol 1091 ◽  
Author(s):  
Hung-Keng Chen ◽  
Po-Tsun Liu ◽  
Ting-Chang Chang ◽  
S.-L. Shy
Keyword(s):  
Conduction Mechanism ◽  
Variable Temperature ◽  
Electrical Measurement ◽  
Isokinetic Temperature ◽  
Trap States ◽  
Band Tail ◽  
Thermally Activated ◽  
Multiple Trapping ◽  
Higher Temperature ◽  
Release Model

AbstractVariable temperature electrical measurement is well-established and used for determining the conduction mechanism in semiconductors. There is a Meyer¡VNeldel relationship between the activation energy and the prefactor with a Meyer¡VNeldel energy of 30.03 meV, which corresponds well with the isokinetic temperature of about 350 K. Therefore, the multiple trapping and release model is properly used to explain the thermally activated phenomenon. By the method, an exponential distribution of traps is assumed to be a better representation of trap states in band tail. Samples with higher temperature during measurement are observed to show better mobility, higher on-current and lower resistance, which agree well with the multiple trapping and release model proposed to explain the conduction mechanism in pentacene-based OTFTs.

Analysis of Carrier Transport Mechanism for p-Type SnO Thin-Film Transistor

2017 ◽  
Vol 748 ◽  
pp. 122-126
Author(s):  
Jian Qin ◽  
Lei Qiang
Keyword(s):  
Thin Film ◽  
Carrier Transport ◽  
Conduction Mechanism ◽  
Thin Film Transistor ◽  
Drain Current ◽  
Thermally Activated ◽  
Multiple Trapping ◽  
P Type ◽  
Tin Monoxide ◽  
Thermally Activated Process

Temperature effect on the I-V characteristics of tin monoxide thin film transistors (SnO TFTs) has been analyzed. The result shows that the drain current of the SnO TFT obeys the Meyer-Neldel rule under low temperature, where current conduction is a thermally activated process. The carrier transport would be dominated by multiple trapping conduction, while, percolation conduction mechanism holds as the temperature increase.

scholarly journals Photoconduction of Polar and Nonpolar Cuts of Undoped Sr0.61Ba0.39Nb2O6 Single Crystals

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 780
Author(s):  
Elke Beyreuther ◽  
Julius Ratzenberger ◽  
Matthias Roeper ◽  
Benjamin Kirbus ◽  
Michael Rüsing ◽  
...  
Keyword(s):  
Electrical Measurement ◽  
Excitation Wavelength ◽  
Trap States ◽  
Strontium Barium Niobate ◽  
Strontium Barium ◽  
Current Voltage ◽  
History Of ◽  
A Current ◽  
Complex Manner

In the last two decades, variably doped strontium barium niobate (SBN) has attracted a lot of scientific interest mainly due to its specific non-linear optical response. Comparably, the parental compound, i.e., undoped SBN, appears to be less studied so far. Here, two different cuts of single-crystalline nominally pure strontium barium niobate in the composition Sr0.61Ba0.39Nb2O6 (SBN61) are comprehensively studied and analyzed with regard to their photoconductive responses. We present conductance measurements under systematically varied illumination conditions along either the polar z-axis or perpendicular to it (x-cut). Apart from a pronounced photoconductance (PC) already under daylight and a large effect upon super-bandgap illumination in general, we observe (i) distinct spectral features when sweeping the excitation wavelength over the sub-bandgap region as then discussed in the context of deep and shallow trap states, (ii) extremely slow long-term relaxation for both light-on and light-off transients in the range of hours and days, (iii) a critical dependence of the photoresponse on the pre-illumination history of the sample, and (iv) a current–voltage hysteresis depending on both the illumination and the electrical-measurement conditions in a complex manner.

Influence of the Distribution of Tail States in a-Si:H on the Field Dependence of Carrier Drift Mobilities

2004 ◽  
Vol 808 ◽  
Author(s):  
Monica Brinza ◽  
Evguenia V. Emelianova ◽  
André Stesmans ◽  
Guy J. Adriaenssens
Keyword(s):  
Field Dependence ◽  
Carrier Mobility ◽  
Transport Model ◽  
Chemical Vapor ◽  
Gaussian Component ◽  
Dispersive Transport ◽  
Exponential Distributions ◽  
Band Tail ◽  
Multiple Trapping ◽  
Gaussian Density

ABSTRACTExponential distributions of tail states have been able, within the framework of a multiple-trapping transport model, to account rather well for the time-of-flight photoconductivity transients that are measured with ‘standard’ a-Si:H, i.e. material prepared by plasma-enhanced chemical vapor deposition at ∼250°C. A field-dependent carrier mobility in the dispersive transport regime is part of the observations. However, samples prepared in an expanding thermal plasma, although still exhibiting the dispersive transients, fail to show this field dependence. The presence of a Gaussian component in the density of valence-band tail states can account for such behavior for the hole transients. Nanoscale ordered inclusions in the amorphous matrix are thought to be responsible for the Gaussian density of states contribution.

RBS/Channeling Diffusion Studies of High Energy Au Implanted Mg Single Crystals

1991 ◽  
Vol 235 ◽  
Author(s):  
R. C. Da Selva ◽  
M. F. Da Silva ◽  
L. Thomé ◽  
A. A. Melo ◽  
J. C. Soares
Keyword(s):  
Single Crystals ◽  
Temperature Regime ◽  
High Energy ◽  
Back Diffusion ◽  
Thermally Activated ◽  
Diffusion Studies ◽  
Higher Temperature ◽  
Diffusion Behaviour ◽  
Thermally Activated Process

ABSTRACTRBS/channeling analyses of high energy Au implantation into Mg are presented. The diffusion behaviour of Au was studied and the occurrence of essentially two distinct regimes were observed: the segregation regime at lower temperatures correlated with the damage introduced by the high energy implantation and the higher temperature regime as a normal thermally activated process of back-diffusion.

Thermally activated polaron tunnelling conduction mechanism in Sr2MnO4 synthesized by quenching in ambient atmosphere

2021 ◽  
Vol 96 (4) ◽  
pp. 045811
Author(s):  
Gurudeo Nirala ◽  
Dharmendra Yadav ◽  
Shail Upadhyay
Keyword(s):  
Conduction Mechanism ◽  
Ambient Atmosphere ◽  
Thermally Activated

The Meyer–Neldel Rule in Conduction Mechanism of the Electrospun ZnO Nanofibers

NANO ◽  
2016 ◽  
Vol 11 (03) ◽  
pp. 1650025 ◽  
Author(s):  
Andrzej Stafiniak ◽  
Marek Tłaczała
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Conduction Mechanism ◽  
Deep Level ◽  
Electrical Measurements ◽  
Thermally Activated ◽  
Theoretical Assumptions ◽  
Different Temperatures ◽  
Zno Nanofibers ◽  
Improved Model

An analytical model describing the conductivity of ZnO nanofibers depending on the grains size is proposed. The research is based on the thermal dc electrical measurements of a single electrospun ZnO nanofiber calcined at different temperatures. In the our previous research, we showed that electrical conduction of ZnO nanofibers is mainly thermally activated. The activation energy of conductivity was strongly dependent on the grain size, which in turn depended on the calcination temperature. This could be due to migration of a point defect in the grain of ZnO and could change the carrier concentration. Our recent studies have shown that ZnO nanofibers behavior is consistent with the Meyer–Neldel rule. This indicates an exponential energy distribution of deep level traps in the material. Based on the theoretical assumptions and experimental data, the improved model of conductivity in a single ZnO nanofiber calcined at different temperatures was proposed.

Capacitance and Transient Photocapacitance Studies of Tetrahedral Amorphous Carbon

2000 ◽  
Vol 621 ◽  
Author(s):  
Kimon C. Palinginis ◽  
A. Ilie ◽  
W.I. Milne ◽  
J. David Cohen
Keyword(s):  
Amorphous Carbon ◽  
Urbach Energy ◽  
Defect Density ◽  
Intrinsic Property ◽  
Band Tail ◽  
Junction Capacitance ◽  
Tetrahedral Amorphous Carbon ◽  
Thermally Activated ◽  
A Value ◽  
Defect Densities

ABSTRACTWe have applied junction capacitance and transient photocapacitance measurements to undoped tetrahedral amorphous carbon (ta-C)/silicon carbide (SiC) heterostructures to deduce defect densities and defect distributions in ta-C. The junction capacitance measurements show two thermally activated processes. One can be related to the activation of carriers out of defects at the ta-C/SiC interface while the other one with an activation energy of 0.36eV is an intrinsic property of the ta-C. The defect density at the ta-C/SiC interface is estimated to be roughly 9 ± 2 × 109 cm−2. The transient photocapacitance measurements have allowed us to observe the broader band tail of ta-C, giving a value (Urbach energy) of 230meV.

Spectroscopic Identification of the Acceptor-Hydrogen Complex in Mg-Doped GaN Grown by MOCVD

1997 ◽  
Vol 468 ◽  
Author(s):  
W. Götz ◽  
M. D. McCluskey ◽  
N. M. Johnson ◽  
D. P. Bour ◽  
E. E. Haller
Keyword(s):  
Hall Effect ◽  
Absorption Spectra ◽  
Thermal Activation ◽  
Variable Temperature ◽  
Chemical Vapor ◽  
Thermally Activated ◽  
Local Vibrational Mode ◽  
Hall Effect Measurements ◽  
Spectroscopic Identification ◽  
Mg Doped

ABSTRACTMg-doped GaN films grown by metalorganic chemical vapor deposition were characterized by variable-temperature Hall-effect measurements and Fourier-transform infrared absorption spectroscopy. As-grown, thermally activated, and deuterated Mg-doped GaN samples were investigated. The existence of Mg-H complexes in GaN is demonstrated with the observation of a local vibrational mode (LVM) at 3125 cm-1 (8 K). At 300 K this absorption line shifts to 3122 cm-1. The intensity of the LVM line is strongest in absorption spectra of as-grown GaN. Mg which is semi-insulating. Upon thermal activation, the intensity of the LVM line significantly decreases and an acceptor concentration of 2×1019cm-3 is derived from the Hall-effect data. After deuteration at 600°C the resistivity of the Mg-doped GaN increased by four orders of magnitude. A LVM line at 2321 cm-1 (8 K) appears in the absorption spectra which is consistent with the isotopie shift of the vibrational frequency when D is substituted for H.

Metastable Phenomena in the Thermally Activated Conductivity of Hydrogenated Amorphous Germanium (a-Ge:H)

1993 ◽  
Vol 297 ◽  
Author(s):  
T. DrÜsedau ◽  
D. Pang ◽  
E. Sauvain ◽  
P. Wickboldt ◽  
E.Z. Liu ◽  
...  
Keyword(s):  
Cooling Rate ◽  
Room Temperature ◽  
Equilibrium Temperature ◽  
Cooling Curves ◽  
Thermally Activated ◽  
Heating And Cooling ◽  
Higher Temperature ◽  
Hydrogenated Amorphous ◽  
Hydrogenated Amorphous Germanium ◽  
Good Agreement

The activated conductivity of a-Ge:H between room temperature and 460K was investigated using heating and cooling rates in the range between .001 and 0.1 K/s. A splitting of the cooling curves obtained at different rates, which defines the so called equilibrium temperature TE, is observed mainly between 420 and 430K. Taking into consideration that TE depends on the maximum cooling rate, the present results are in good agreement with those reported by Eberhardt et al. The higher cooling rate always leads to the lower conductivity at any temperature below TE. These effects can be rationalized in terms of a reversible shift of the Fermi level towards midgap at higher temperature. Though reversible changes of the mobility cannot be excluded, they cannot account for our set of experimental data. Rather, changes in the density of electronic states within the mobility gap can explain the effects observed.

Band tail hopping conduction mechanism in highly conductive amorphous carbon nitride thin films

2004 ◽  
Vol 85 (25) ◽  
pp. 6176-6178 ◽  
Author(s):  
G. Lazar ◽  
K. Zellama ◽  
M. Clin ◽  
C. Godet
Keyword(s):  
Thin Films ◽  
Amorphous Carbon ◽  
Carbon Nitride ◽  
Conduction Mechanism ◽  
Hopping Conduction ◽  
Band Tail ◽  
Amorphous Carbon Nitride
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