Variations in the photoconductivity and in the electrical counting properties of diamonds

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.

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Effect of Cu doping on the electrical Properties of ZnTe by Vacuum Thermal Evaporation

Ibn AL- Haitham Journal For Pure and Applied Science ◽

10.30526/31.3.2023 ◽

2018 ◽

Vol 31 (3) ◽

pp. 20

Author(s):

Sarmad M. M. Ali ◽

Alia A.A. Shehab ◽

Samir A. Maki

Keyword(s):

Activation Energy ◽

Electrical Conductivity ◽

Hall Effect ◽

Carrier Concentration ◽

Hall Mobility ◽

Cu Doping ◽

Before And After ◽

Hall Effect Measurements ◽

Evaporation Technique ◽

P Type

In this study, the ZnTe thin films were deposited on a glass substrate at a thickness of 400nm using vacuum evaporation technique (2×10-5mbar) at RT. Electrical conductivity and Hall effect measurements have been investigated as a function of variation of the doping ratios (3,5,7%) of the Cu element on the thin ZnTe films. The temperature range of (25-200°C) is to record the electrical conductivity values. The results of the films have two types of transport mechanisms of free carriers with two values of activation energy (Ea1, Ea2), expect 3% Cu. The activation energy (Ea1) increased from 29meV to 157meV before and after doping (Cu at 5%) respectively. The results of Hall effect measurements of ZnTe , ZnTe:Cu films show that all films were (p-type), the carrier concentration (1.1×1020 m-3) , Hall mobility (0.464m2/V.s) for pure ZnTe film, increases the carrier concentration (6.3×1021m-3) Hall mobility (2m2/V.s) for doping (Cu at 3%) film, but decreases by increasing Cu concentration.

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The relationship between chemical composition and electrical conductivity of some North American micas

Canadian Journal of Physics ◽

10.1139/p77-040 ◽

1977 ◽

Vol 55 (3) ◽

pp. 270-275 ◽

Cited By ~ 11

Author(s):

J. P. Crine ◽

A. Friedmann ◽

M. R. Wertheimer ◽

A. Yelon

Keyword(s):

Electrical Conductivity ◽

Chemical Composition ◽

Electric Field ◽

North American ◽

Room Temperature ◽

Percolation Model ◽

The Relationship ◽

Field Strengths

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.

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The characterization of pure and niobium-doped crystals of strontium titanate using Hall, electrical conductivity, and optical absorption data

Canadian Journal of Physics ◽

10.1139/p78-059 ◽

1978 ◽

Vol 56 (4) ◽

pp. 453-467 ◽

Cited By ~ 41

Author(s):

G. Perluzzo ◽

J. Destry

Keyword(s):

Heat Treatment ◽

Electrical Conductivity ◽

Optical Absorption ◽

Hall Effect ◽

Strontium Titanate ◽

Defect States ◽

Absorption Data ◽

Niobium Doped ◽

Hall Effect Measurements

A description is given of the heat treatment, under controlled conditions, of crystals of strontium titanate, both pure and niobium-doped, and of the effect of this treatment on the defect states in this material. Our analysis is based on evaluation of the results of electrical conductivity and Hall effect measurements, and those of optical absorption.

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Influence of Cs, Ba, Th and Cu adsorption and electric field on the Hall effect and electrical conductivity of Ni thin films

Vacuum ◽

10.1016/0042-207x(67)90745-2 ◽

1967 ◽

Vol 17 (7) ◽

pp. 423

Keyword(s):

Thin Films ◽

Electrical Conductivity ◽

Electric Field ◽

Hall Effect

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Growth of (110) GaAs/GaAs by Molecular Beam Epitaxy

MRS Proceedings ◽

10.1557/proc-46-391 ◽

1985 ◽

Vol 46 ◽

Cited By ~ 2

Author(s):

L.T. Parechanian ◽

E.R. Weber ◽

T.L. Hierl

Keyword(s):

Molecular Beam Epitaxy ◽

Substrate Temperature ◽

Hall Effect ◽

Room Temperature ◽

Molecular Beam ◽

Defect Density ◽

Temperature Dependent ◽

Mbe Growth ◽

Order Of Magnitude ◽

Hall Effect Measurements

AbstractThe simultaneous molecular beam epitaxy (MBE) growth of (100) and (110) GaAs/GaAsintentionally doped with Si(∼lE16/cm^3) was studied as a function of substrate temperature, arsenic overpressure, and epitaxial growth rate. The films wereanalyzed by scanning electron and optical microscopy, liquid helium photoluminescence (PL), and electronic characterization.For the (110) epitaxal layers, an increase in morphological defect density and degradation of PL signal was observed with a lowering of the substrate temperature from 570C. Capacitance-voltage (CV) and Hall Effect measurements yield room temperature donor concentrations for the (100) films of n∼l5/cm^3 while the (110) layers exhibit electron concentrations of n∼2El7/cm^3. Hall measurements at 77K on the (100) films show the expected mobility enhancement of Si donors, whereas the (110) epi layers become insulating or greatly compensated. This behavior suggests that room temperature conduction in the (110) films is due to a deeper donor partially compensated by an acceptor level whose concentration is of the same order of magnitude as that of any electrically active Si. Temperature dependent Hall effect indicates that the activation energy of the deeper donor level lies ∼290 meV from the conduction band. PL and Hall effect indicate that the better quality (110) material is grown by increasingthe arsenic flux during MBE growth. The nature of the defects involved with the growth process will be discussed.

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Hall Effect Measurements on New Thermoelectric Materials

MRS Proceedings ◽

10.1557/proc-793-s8.35 ◽

2003 ◽

Vol 793 ◽

Author(s):

Jarrod Short ◽

Sim Loo ◽

Sangeeta Lal ◽

Kuei Fang Hsu ◽

Eric Quarez ◽

...

Keyword(s):

Thermal Conductivity ◽

Electrical Conductivity ◽

Hall Effect ◽

Measurement System ◽

Material Properties ◽

Figure Of Merit ◽

New Materials ◽

Temperature Dependent ◽

Additional Insight ◽

Hall Effect Measurements

ABSTRACTIn the field of thermoelectrics, the figure of merit of new materials is based on the electrical conductivity, thermoelectric power, and thermal conductivity of the sample, however additional insight is gained through knowledge of the carrier concentrations and mobility in the materials. The figure of merit is commonly related to the material properties through the B factor which is directly dependent on the mobility of the carriers as well as the effective mass.To gain additional insight on the new materials of interest for thermoelectric applications, a Hall Effect system has been developed for measuring the temperature dependent carrier concentrations and mobilities. In this paper, the measurement system will be described, and recent results for several new materials will be presented.

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Hall Effect Measurements On SixGe1−x Bulk Alloys

MRS Proceedings ◽

10.1557/proc-442-381 ◽

1996 ◽

Vol 442 ◽

Cited By ~ 1

Author(s):

T. Mchedlidze ◽

I. Yonenaga

Keyword(s):

Hall Effect ◽

Carrier Transport ◽

Czochralski Method ◽

Charge Carriers ◽

Transport Measurement ◽

Type Conductivity ◽

Measurement Results ◽

Hall Effect Measurements ◽

Bulk Alloys ◽

Additional Charge

AbstractCarrier transport measurement results for SixGe1−x bulk alloys with 0.03≤x≤0.9, grown by the Czochralski method are presented. Both monocrystalline (x=0.03 and x=0.23) and polycrystalline (x=0.12, 0.25, 0.4, 0.5, 0.75, 0.9) samples were analyzed. In all samples additional charge carriers were created during growth or/and cooling of crystals. With n-type starting materials only alloy with x=0.9 revealed n-type conductivity, all other alloys were of ptype. Creation of acceptors in the SixGe1−x alloy grown by Czochralski method is maximal for 0.4≤x≤0.75.

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Optical and electrical study of cap layer effect in QHE devices with double-2DEG

MRS Proceedings ◽

10.1557/opl.2013.1160 ◽

2013 ◽

Vol 1617 ◽

pp. 31-36 ◽

Cited By ~ 1

Author(s):

L. Zamora-Peredo ◽

I. Cortes-Mestizo ◽

L. García-Gonzáez ◽

J. Hernández-Torres ◽

T. Hernandez-Quiroz ◽

...

Keyword(s):

Electric Field ◽

Room Temperature ◽

Quantum Hall ◽

Three Samples ◽

Cap Layer ◽

Layer Effect ◽

Hall Effect Measurements ◽

Band Profile ◽

Surface Electric Field ◽

Dimensional Electron Gas

ABSTRACTIn this work we report on the characteristics of GaAs/AlGaAs heterostructures with a symmetric double two-dimensional electron gas (D-2DEG). Optical characterization was made by room temperature photoreflectance (PR) spectroscopy as well as electrical properties were determinated using the quantum Hall effect measurements at 2K. In order to study the surface effects on the conduction band profile, three samples with different GaAs cap layer thickness (25, 60 and 80 nm) were grown by the molecular beam epitaxy. Photoreflectance spectra at room temperature show the wide-period Franz-Keldysh oscillations between 1.42 and 1.70 eV originated by the surface electric field. The analysis of these oscillations shows that the surface electric field varies from 503 to 120 kV/cm whereas the thickness of the cap layer increases that was produced by the reduction of the depletion zone near the surface. Using QHE measurements we found that electron density increases if the surface electric field decreases.

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