A Contribution to a Method for Determining the Mobilities of Natural Charge Carriers in Highly Insulating Organic Liquids

1971 ◽  
Vol 75 (6) ◽  
pp. 547-548
Author(s):  
H. v. Löhneysen ◽  
G. Kleinheins
Keyword(s):  
Charge Carriers ◽  
Organic Liquids ◽  
Natural Charge

Nachweis der Volumen-Ionisation in organischen Flüssigkeiten

1965 ◽  
Vol 20 (3) ◽  
pp. 394-400
Author(s):  
H. Bässler ◽  
P. Mayer ◽  
N. Riehl
Keyword(s):  
Positive Charge ◽  
Activation Energies ◽  
Dc Conductivity ◽  
Charge Carriers ◽  
Dielectric Liquid ◽  
Organic Liquids ◽  
Constant Field ◽  
Bulk Conductivity ◽  
Positive Ions ◽  
The Law

In order to study the bulk-conductivity in organic liquids measurements with blocking quartzelectrodes were made. When applying a constant field, a bulk-current through the dielectric liquid can be observed, which is decreasing exponentiallyjd(t)=j0_ exp {—t/R_C}+j0 exp {—t/R+ C}.R- and R+ are the bulk-resistivities for negative and positive charge-carriers, from which the bulk-conductivity of the liquid can be calculated. It is identical with the dc.-conductivity measured with conducting electrodes, that is it obeys the law:σ=σ01 exp { —E1/k T} +σ02 exp {—E.2/k T}.Therefore the generation of charge-carriers must be independent of the electrodes and the activation-energies E1 and E2 must correlate with ionisation within the liquid. The mobility of negative carriers is about two or three times that of positive ones. This fact leads to conclusions concerning the nature of the carriers. A tunnel-process is proposed to explain the discharging of positive ions at a metallic cathode.

Über die Ladungsträgererzeugung in Lösungen, die Stickstoff-Heterocyclen enthalten

1965 ◽  
Vol 20 (2) ◽  
pp. 227-234
Author(s):  
H. Bässler ◽  
N. Riehl
Keyword(s):  
Activation Energy ◽  
Aromatic Hydrocarbons ◽  
Charge Carriers ◽  
Organic Liquids ◽  
Charge Transfer Complexes ◽  
Separation Energy ◽  
Proposed Model ◽  
Bimolecular Recombination ◽  
Short Time ◽  
Coulomb Part

In preceeding papers a model for the generation of charge carriers in organic liquids was developed. The activation energy of the dc-conductivity specific for one compound was said to be the sum of a resonance and a COULOMB part: E1 = E+½3 ET (the factor ½ is due to bimolecular recombination) . Measurements with aza-compounds show that E1 is decreasing linearily with increasing calculated π-electron-density at the N-atom. This fact argues for electrons to be the majority chargecarriers. E′ is the energy necessary to localize one electron at the N-atom for a short time, ET is the further separation-energy. With charge-transfer-complexes formed by acridine with aromatic hydrocarbons, E′ increases proportional to the electron-affinity of the hydrocarbons. For energetic reasons it can be assumed that the separated electron moves as a solvatised one through the liquid. An extrapolation shows that the proposed model holds for unsubstituted aromatic hydrocarbons too, but not for aliphatic ones. This is confirmed by experiments. Furthermore, arguments will be developed to distinguish between the conductivity specific for one compound and the conductivity due to impurities. In certain cases the impurity concentration can be estimated from the σ(1/T) curve.

Detector strategies for environmental scanning electron microscopy

1992 ◽  
Vol 50 (2) ◽  
pp. 1296-1297
Author(s):  
Klaus-Ruediger Peters
Keyword(s):  
High Vacuum ◽  
Environmental Scanning Electron Microscopy ◽  
Charge Carriers ◽  
Environmental Scanning ◽  
Surface Information ◽  
X Ray ◽  
Detector Electrode ◽  
Electrons And Ions ◽  
Low Energy Electrons ◽  
Environmental Sem

Environmental SEM operate at specimen chamber pressures of ∼20 torr (2.7 kPa) allowing stabilization of liquid water at room temperature, working on rugged insulators, and generation of an environmental secondary electron (ESE) signal. All signals available in conventional high vacuum instruments are also utilized in the environmental SEM, including BSE, SE, absorbed current, CL, and X-ray. In addition, the ESEM allows utilization of the flux of charge carriers as information, providing exciting new signal modes not available to BSE imaging or to conventional high vacuum SEM.In the ESEM, at low vacuum, SE electrons are collected with a “gaseous detector”. This detector collects low energy electrons (and ions) with biased wires or plates similar to those used in early high vacuum SEM for SE detection. The detector electrode can be integrated into the first PLA or positioned at any other place resulting in a versatile system that provides a variety of surface information.

Direct imaging of charge transfer

1996 ◽  
Vol 54 ◽  
pp. 680-681
Author(s):  
Yimei Zhu ◽  
J. Tafto
Keyword(s):  
Charge Transfer ◽  
Electron Diffraction ◽  
Scattering Amplitude ◽  
High Temperature Superconductors ◽  
Charge Carriers ◽  
Image Charge ◽  
Net Charge ◽  
Long Time ◽  
Electron Holes ◽  
First Time

The electron holes confined to the CuO2-plane are the charge carriers in high-temperature superconductors, and thus, the distribution of charge plays a key role in determining their superconducting properties. While it has been known for a long time that in principle, electron diffraction at low angles is very sensitive to charge transfer, we, for the first time, show that under a proper TEM imaging condition, it is possible to directly image charge in crystals with a large unit cell. We apply this new way of studying charge distribution to the technologically important Bi2Sr2Ca1Cu2O8+δ superconductors.Charged particles interact with the electrostatic potential, and thus, for small scattering angles, the incident particle sees a nuclei that is screened by the electron cloud. Hence, the scattering amplitude mainly is determined by the net charge of the ion. Comparing with the high Z neutral Bi atom, we note that the scattering amplitude of the hole or an electron is larger at small scattering angles. This is in stark contrast to the displacements which contribute negligibly to the electron diffraction pattern at small angles because of the short g-vectors.

Laser Engineering of Barrier Structures Based on Solid Solution ZnCdHgTe.

2002 ◽  
Vol 719 ◽  
Author(s):  
Galina Khlyap
Keyword(s):  
Room Temperature ◽  
Film Surface ◽  
Charge Carriers ◽  
Barrier Structure ◽  
Free Charge ◽  
Current Voltage ◽  
Capacitance Voltage ◽  
Laser Engineering ◽  
Charged Defects ◽  
Epilayer Surface

AbstractRoom-temperature electric investigations carried out in CO2-laser irradiated ZnCdHgTe epifilms revealed current-voltage and capacitance-voltage dependencies typical for the metal-semiconductor barrier structure. The epilayer surface studies had demonstrated that the cell-like relief has replaced the initial tessellated structure observed on the as-grown samples. The detailed numerical analysis of the experimental measurements and morphological investigations of the film surface showed that the boundaries of the cells formed under the laser irradiation are appeared as the regions of accumulation of derived charged defects of different type of conductivity supplying free charge carriers under the applied electric field.

Effect of Illumination on Organic Polymer Thin-Film Transistors

2003 ◽  
Vol 771 ◽  
Author(s):  
Michael C. Hamilton ◽  
Sandrine Martin ◽  
Jerzy Kanicki
Keyword(s):  
Thin Film ◽  
Thin Film Transistors ◽  
Drain Current ◽  
Charge Carriers ◽  
Electrical Performance ◽  
Organic Polymer ◽  
Light Illumination ◽  
Polymer Thin Film ◽  
Channel Region ◽  
White Light Illumination

AbstractWe have investigated the effects of white-light illumination on the electrical performance of organic polymer thin-film transistors (OP-TFTs). The OFF-state drain current is significantly increased, while the drain current in the strong accumulation regime is relatively unaffected. At the same time, the threshold voltage is decreased and the subthreshold slope is increased, while the field-effect mobility of the charge carriers is not affected. The observed effects are explained in terms of the photogeneration of free charge carriers in the channel region due to the absorbed photons.

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