Impurity-Induced Defect States in Pb1−xGexTe Alloys Doped With Gallium

1999 ◽  
Vol 607 ◽  
Author(s):  
E.P. Skipetrov ◽  
E.A. Zvereva ◽  
V.V. Belousov ◽  
L.A. Skipetrova
Keyword(s):  
Low Temperature ◽  
Heat Source ◽  
Single Crystals ◽  
Deep Level ◽  
Persistent Photoconductivity ◽  
Background Illumination ◽  
Defect States ◽  
Galvanomagnetic Properties ◽  
Controlled Illumination ◽  
Temperature Activation

AbstractGalvanomagnetic properties of n-Pb1−xGexTe<Ga>(O.04≤x≤O.08) single crystals have been investigated in the shielded from external background illumination chamber and under controlled illumination from infrared heat source. Low temperature activation range of the impurity conductivity on the dark curves of ρ(l/T) was revealed and attributed to the appearance of gallium-induced deep level EGa in the gap of the alloys. It was shown that the alloys possess high infrared photosensitivity at temperatures below Tc=50%60 K, and effect of the persistent photoconductivity at helium temperatures was revealed.

Infrared Photosensitivity Due to the Yb-Induced Defect States in Pb1−xGexTe Alloys

1999 ◽  
Vol 607 ◽  
Author(s):  
E.P. Skipetrov ◽  
N.A. Chernova ◽  
E.A. Zvereva ◽  
E.I. Slyn'ko
Keyword(s):  
Persistent Photoconductivity ◽  
Helium Temperature ◽  
Defect States ◽  
Galvanomagnetic Properties ◽  
Jahn Teller ◽  
Kinetics Of

AbstractGalvanomagnetic properties and photoconductivity kinetics of Pb1−xGexTe(x≤0.04) alloys doped with Yb have been investigated. The alloys exhibit high infrared photosensitivity at temperature under 40 K; at helium temperature, the effect of persistent photoconductivity has been observed. The photoconductivity kinetics after terminating of infrared illumination consists of a fast and a long-term relaxation regions. We explain the observed effects by a capture of electrons into the Yb-induced states, that are subjected to the Jahn-Teller instability. The parameters of the Jahn-Teller states are estimated.

Influence of annealing on the electrical conductivity of single crystals of Cu2O

1970 ◽  
Vol 48 (1) ◽  
pp. 63-69 ◽  
Author(s):  
F. L. Weichman ◽  
R. Kužel
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Low Temperature ◽  
Single Crystals ◽  
Activation Energies ◽  
Conductivity Measurements ◽  
Different Temperatures ◽  
Temperature Activation ◽  
The Stability ◽  
Stability Ranges

A series of conductivity measurements were made on single crystals of Cu2O from 20 to 840 °C to explain the various activation energies which appear at different temperatures and oxygen pressures. Crystals were annealed in the 10−8 and 10−4 Torr region in the stability ranges of Cu2O, Cu, and CuO at various temperatures. For the low-temperature activation energies ranging from 0.60 to 0.26 eV, an excellent agreement with the empirical Meyer–Neldel rule was found. The highest activation energy of 1.12 eV in the 570 to 680 °C range at 10−8 Torr is associated with the boundary between the two stable phases Cu and Cu2O. The changes in defect concentration are ascribed to the mechanism of self-compensation. The energy-level diagram proposed by Bloem is adequate to explain the present results.

Laplace current deep level transient spectroscopy measurements of defect states in methylammonium lead bromide single crystals

2017 ◽  
Vol 122 (14) ◽  
pp. 145701 ◽  
Author(s):  
John W. Rosenberg ◽  
Matshisa J. Legodi ◽  
Yevgeny Rakita ◽  
David Cahen ◽  
Mmantsae Diale
Keyword(s):  
Single Crystals ◽  
Deep Level Transient Spectroscopy ◽  
Deep Level ◽  
Defect States ◽  
Lead Bromide ◽  
Transient Spectroscopy

LOW-TEMPERATURE TRANSITION METAL-SEMICONDUCTOR IN CdCr2Se4 SINGLE CRYSTALS DOPED WITH INDIUM AND GALLIUM

1980 ◽  
Vol 41 (C5) ◽  
pp. C5-155-C5-156 ◽  
Author(s):  
T. G. Aminov ◽  
K. P. Below ◽  
V. T. Kalinnikov ◽  
L. I. Koroleva ◽  
L. N. Tovmasjan
Keyword(s):  
Low Temperature ◽  
Transition Metal ◽  
Single Crystals ◽  
Temperature Transition

Persistent Photoconductivity And Thermal Recovery Kinetics Of Low Energy Ar + Bombarded GaAs

1991 ◽  
Vol 223 ◽  
Author(s):  
A. Vaseashta ◽  
L. C. Burton
Keyword(s):  
Deep Level Transient Spectroscopy ◽  
Deep Level ◽  
Thermal Recovery ◽  
Low Energy ◽  
Persistent Photoconductivity ◽  
Transport Parameters ◽  
Excellent Correlation ◽  
Proposed Model ◽  
Transient Spectroscopy ◽  
Kinetics Of

ABSTRACTKinetics of persistent photoconductivity, photoquenching, and thermal and optical recovery observed in low energy Ar+ bombarded on (100) GaAs surfaces have been investigated. Rate and transport equations for these processes were derived and simulated employing transport parameters, trap locations and densities determined by deep level transient spectroscopy. Excellent correlation was obtained between the results of preliminary simulation and the experimentally observed values. The exponential decay of persistent photoconductivity response curve was determined to be due to metastable electron traps with longer lifetime and is consistent with an earlier proposed model.

Spectrum of Defect States in Porous Organic Low-k Dielectric Films, Annealed in Argon and Nitrogen

2003 ◽  
Vol 766 ◽  
Author(s):  
V. Ligatchev ◽  
T.K.S. Wong ◽  
T.K. Goh ◽  
Rusli Suzhu Yu
Keyword(s):  
Deep Level ◽  
Dielectric Films ◽  
Silicon Substrates ◽  
Reverse Bias Voltage ◽  
Defect States ◽  
Single Side ◽  
Sandwich Type ◽  
Transient Spectroscopy ◽  
P Type ◽  
Spectrum Deconvolution

AbstractDefect spectrum N(E) of porous organic dielectric (POD) films is studied with capacitance deep-level-transient-spectroscopy (C-DLTS) in the energy range up to 0.7 eV below conduction band bottom Ec. The POD films were prepared by spin coating onto 200mm p-type (1 – 10 Δcm) single-side polished silicon substrates followed by baking at 325°C on a hot plate and curing at 425°C in furnace. The film thickness is in the 5000 – 6000 Å range. The ‘sandwich’ -type NiCr/POD/p-Si/NiCr test structures showed both rectifying DC current-voltage characteristics and linear 1/C2 vs. DC reverse bias voltage. These confirm the applicability of the C-DLTS technique for defect spectrum deconvolution and the n-type conductivity of the studied films. Isochronal annealing (30 min in argon or 60 min in nitrogen) has been performed over the temperature range 300°C - 650°C. The N(E) distribution is only slightly affected by annealing in argon. However, the distribution depends strongly on the annealing temperature in nitrogen ambient. A strong N(E) peak at Ec – E = 0.55 – 0.60 eV is detected in all samples annealed in argon but this peak is practically absent in samples annealed in nitrogen at Ta < 480°C. On the other hand, two new peaks at Ec – E = 0.12 and 0.20 eV appear in the N(E) spectrum of the samples annealed in nitrogen at Ta = 650°C. The different features of the defect spectrum are attributed to different interactions of argon and nitrogen with dangling carbon bonds on the intra-pore surfaces.

scholarly journals Correlation between Defects and Electrical Performances of Ion-Irradiated 4H-SiC p–n Junctions

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1966
Author(s):  
Domenico Pellegrino ◽  
Lucia Calcagno ◽  
Massimo Zimbone ◽  
Salvatore Di Franco ◽  
Antonella Sciuto
Keyword(s):  
Deep Level ◽  
Electrical Characterization ◽  
High Fluence ◽  
Defect States ◽  
Exponential Parameter ◽  
Current Voltage ◽  
Different Temperatures ◽  
In Series ◽  
Transient Spectroscopy ◽  
Fluence Range

In this study, 4H-SiC p–n junctions were irradiated with 700 keV He+ ions in the fluence range 1.0 × 1012 to 1.0 × 1015 ions/cm2. The effects of irradiation were investigated by current–voltage (I–V) and capacitance–voltage (C–V) measurements, while deep-level transient spectroscopy (DLTS) was used to study the traps introduced by irradiation defects. Modifications of the device’s electrical performances were observed after irradiation, and two fluence regimes were identified. In the low fluence range (≤1013 ions/cm2), I–V characteristics evidenced an increase in series resistance, which can be associated with the decrease in the dopant concentration, as also denoted by C–V measurements. In addition, the pre-exponential parameter of junction generation current increased with fluence due to the increase in point defect concentration. The main produced defect states were the Z1/2, RD1/2, and EH6/7 centers, whose concentrations increased with fluence. At high fluence (>1013 ions/cm2), I–V curves showed a strong decrease in the generation current, while DLTS evidenced a rearrangement of defects. The detailed electrical characterization of the p–n junction performed at different temperatures highlights the existence of conduction paths with peculiar electrical properties introduced by high fluence irradiation. The results suggest the formation of localized highly resistive regions (realized by agglomeration of point defects) in parallel with the main junction.

scholarly journals Analysis and Comparison of Some Low-Temperature Heat Sources for Heat Pumps

Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1853 ◽  
Author(s):  
Pavel Neuberger ◽  
Radomír Adamovský
Keyword(s):  
Heat Transfer ◽  
Low Temperature ◽  
Heat Source ◽  
Heat Pump ◽  
Heat Exchangers ◽  
Ambient Air ◽  
Heat Transfer Fluid ◽  
Heat Sources ◽  
Ground Heat Exchangers ◽  
Temperature Heat

The efficiency of a heat pump energy system is significantly influenced by its low-temperature heat source. This paper presents the results of operational monitoring, analysis and comparison of heat transfer fluid temperatures, outputs and extracted energies at the most widely used low temperature heat sources within 218 days of a heating period. The monitoring involved horizontal ground heat exchangers (HGHEs) of linear and Slinky type, vertical ground heat exchangers (VGHEs) with single and double U-tube exchanger as well as the ambient air. The results of the verification indicated that it was not possible to specify clearly the most advantageous low-temperature heat source that meets the requirements of the efficiency of the heat pump operation. The highest average heat transfer fluid temperatures were achieved at linear HGHE (8.13 ± 4.50 °C) and double U-tube VGHE (8.13 ± 3.12 °C). The highest average specific heat output 59.97 ± 41.80 W/m2 and specific energy extracted from the ground mass 2723.40 ± 1785.58 kJ/m2·day were recorded at single U-tube VGHE. The lowest thermal resistance value of 0.07 K·m2/W, specifying the efficiency of the heat transfer process between the ground mass and the heat transfer fluid, was monitored at linear HGHE. The use of ambient air as a low-temperature heat pump source was considered to be the least advantageous in terms of its temperature parameters.

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