Paramagnetic Resonance Study of Fermi Level Motion and Defect Formation in High-Resistivity Cadmium Sulfide Crystals

1964 ◽  
Vol 68 (12) ◽  
pp. 3907-3910 ◽  
Author(s):  
G. A. Somorjai ◽  
R. S. Title
Keyword(s):  
Fermi Level ◽  
Cadmium Sulfide ◽  
Defect Formation ◽  
High Resistivity ◽  
Paramagnetic Resonance

Interaction of Point Defects with Impurities in the Si-SiO2 System and its Influence on the Properties of the Interface

2009 ◽  
Vol 156-158 ◽  
pp. 145-148 ◽  
Author(s):  
Daniel Kropman ◽  
E. Mellikov ◽  
K. Lott ◽  
Tiit Kärner ◽  
Ivo Heinmaa ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Magnetic Resonance ◽  
Fermi Level ◽  
Point Defects ◽  
Interface Properties ◽  
Hydrogen Ions ◽  
Paramagnetic Resonance ◽  
Proposed Model ◽  
P Type ◽  
Electron Paramagnetic

The results of investigation of the point defect generation and interaction with impurities in the Si-SiO2 system during the process of its formation by means of electron paramagnetic resonance (EPR) and nucleous magnetic resonance (NMR) technique are presented. It has been shown that the diference in point defects interaction with hydrogen at the Si-SO2 interface with n- and p-type conductivity are connected with the sign of hydrogen ions incorporation dependence on the Fermi level position in accordance with the proposed model. The interface properties may be improved by laser irradiation.

Application of the Amphoteric Native Defect Model to Diffusion and Activation of Shallow Impurities in III-V Semiconductors

1993 ◽  
Vol 300 ◽  
Author(s):  
W. Walukiewicz
Keyword(s):  
Fermi Level ◽  
Defect Formation ◽  
Doped Semiconductors ◽  
Model Calculations ◽  
Impurity Atoms ◽  
Dependent Part ◽  
Localized Defects ◽  
Shallow Impurities ◽  
And Diffusion ◽  
Lattice Matched

ABSTRACTThe effects of heavy doping on the formation of charged point defects are considered. It is shown that the Fermi level dependent part of the formation energy of highly localized defects can be determined using a universal energy reference, common to all III-V compound semiconductors. The concept is used to analyze the electrical activity and diffusion of dopant impurities in these compounds. We present model calculations which explain the correlation between the maximum hole concentrations and the acceptor impurity diffusion in InP and in InGaAs alloys, doped with group II acceptors. The calculations account for the redistribution of the impurity atoms at the lattice matched InP/InGaAs interface. It is also demonstrated that an abrupt enhancement of the Fermi level induced defect formation is observed at the onset of highly degenerate statistics in heavily doped semiconductors.

Effect of Bias on Recovery Rates of Stressed Amorphous Silicon Mis Structures

1990 ◽  
Vol 192 ◽  
Author(s):  
W. B. Jackson ◽  
M. Hack
Keyword(s):  
Fermi Level ◽  
Amorphous Silicon ◽  
Conduction Band ◽  
Defect Formation ◽  
Defect States ◽  
Theoretical Understanding ◽  
Fermi Level Position ◽  
Electron Accumulation ◽  
Capacitance Voltage ◽  
Mis Structures

ABSTRACTThe effect of Fermi level position on the annealing of defects created by electron accumulation is investigated. Results indicate that holes accelerate the annealing of defects created by electrons confirming the theoretical understanding of the proximity compensated layer. Capacitance-voltage curves indicate that hole accumulation tends to create defect states located closer to the conduction band than electron accumulation–a result in agreement with energetics of defect formation.

Preparation and characterization of polyaniline–cadmium sulfide nanocomposite for gas sensor application

2017 ◽  
Vol 31 (26) ◽  
pp. 1750234 ◽  
Author(s):  
Selma M. H. Al-Jawad ◽  
Sewench N. Rafic ◽  
Mustafa M. Muhsen
Keyword(s):  
Cadmium Sulfide ◽  
Oxidative Polymerization ◽  
Sol Gel ◽  
High Resistivity ◽  
Emeraldine Salt ◽  
Electrical Measurements ◽  
Salt Form ◽  
Operation Temperature ◽  
Cds Nanocomposites

Polyaniline (PANI) was prepared by chemical oxidative polymerization of aniline monomers as emeraldine salt form. By the same method, polyaniline–cadmium sulfide nanocomposites were synthesized in the presence of different percentages (10–50 wt.%) of cadmium sulfide (CdS) which was prepared by using sol–gel method. The optical band gap was decrease with increasing of CdS concentration, that is obtained from UV-VIS measurements. From SEM and AFM, there is uniform distribution for cadmium sulfide nanoparticles in the PANI matrix. The electrical measurements of nanocomposites exhibit the effect of crystallite size and the high resistivity of CdS on the resistivity of nanocomposites. Emeraldine salt PANI, CdS and PANI–CdS nanocomposites were investigated as gas sensors. From this investigation, the sensitivity of PANI–CdS for NO2 gas increase with the increasing of operation temperature and the optimum sensitivity was obtained at 200[Formula: see text]C. The sensitivity of nanocomposites at best temperature (200[Formula: see text]C) was increased and faster response time with the increasing of CdS contents.

Photo EPR Study of Trapping and Recombination Processes in Semi-Insulating 4H-SiC Crystals as Function of Temperature

2001 ◽  
Vol 680 ◽  
Author(s):  
E.N. Kalabukhova ◽  
S.N. Lukin ◽  
A. Saxler ◽  
W.C. Mitchel ◽  
S R. Smith ◽  
...  
Keyword(s):  
Fermi Level ◽  
Deep Level ◽  
Antisite Defect ◽  
Shallow Donor ◽  
Epr Spectrum ◽  
Paramagnetic Resonance ◽  
Line Intensities ◽  
Donor And Acceptor ◽  
Recombination Processes ◽  
Deep Donor

ABSTRACTPhoto-Electron Paramagnetic Resonance (photo-EPR) measurements of semi-insulating (s.-i.) 4H SiC have been made at 37 GHz including photo excitation and photo quenching techniques in the temperature interval from 77 K to 50 K. At T = 77 K in the dark the EPR spectrum consists of a low intensity line due to boron on the cubic lattice site and a single line with isotropic g∥ = g⊥ = 2.0025 due to a carbon-related surface defect. During illumination with ultraviolet light the EPR lines of hexagonal boron and cubic nitrogen appear in the EPR spectrum and persist after the illumination is removed. Subsequent illumination of the sample with sub-band gap, visible, light resulted in the quenching of the EPR lines from nitrogen and appearance of the IP1EPR line with g∥ = 2.0048, g⊥ = 2.0030 caused by direct transfer of electrons from nitrogen donor to the P1 center. The lifetime of the photo-generated carriers trapped by the P1 centers is found to be more than 15- 20 hours after the photo-excitation was turned off. The deep donor P1 local center is suggested to be the as yet unidentified deep level located at EC – 1.1 eV which pins the Fermi level in this sample at this energy in the dark. As the temperature is lowered from 77K and the quasi Fermi level positions reach shallow donor and acceptor states, an additional EPR line, ID, with g∥ = 2.0063, g⊥ = 2.0006, appears at 50 K in the excitation EPR spectrum and is attributed to the antisite defect Si−c with an energy level shallower than nitrogen. At the same time the ratio of the photo-excited EPR line intensities responsible for boron on the cubic and hexagonal sites, IkB:IhB, returns to the value observed at 77 K and becomes equal to 0.4 at 50 K, showing that the concentration of boron in the hexagonal site is higher than on the cubic site.

EPR Study of the Role of Hydrogen in the Defect Formation Upon Heat Treatment of Oxidized SiC

1998 ◽  
Vol 513 ◽  
Author(s):  
P. J. Macfarlane ◽  
M. E. Zvanut
Keyword(s):  
Heat Treatment ◽  
Defect Formation ◽  
Wide Band ◽  
Oxide Semiconductor ◽  
Wide Band Gap ◽  
Paramagnetic Resonance ◽  
Hydrogen Incorporation ◽  
Si Substrates ◽  
Mos Devices ◽  
Dry Heat Treatment

ABSTRACTFor the past several years hydrogen incorporation in metal oxide semiconductor (MOS) devices has been of interest because studies have shown that vacuum annealing of oxidized Si substrates desorbs hydrogen, revealing interfacial defects. Today, in applications that require higher power and/or temperature, Si will likely be replaced with a wide-band-gap semiconductor. For MOS devices, SiC is a leading contender because it can be thermally oxidized to form a SiO2 insulating layer similar to Si. However, the SiC/SiO2 structure potentially contains hydrogen sensitive centers similar to those found in Si/SiO2 structures. Using electron paramagnetic resonance (EPR), we have observed a center 1.8 G wide peak-to-peak at g=2.0026. The center is generated in oxidized SiC that has received a 900° C dry, N2 or O2, post oxidation heat-treatment in which moisture is measured to be less than 1 ppm. Annealing at 900° C in standard Ar containing at least 50 ppm H2O decreases the center's concentration by two orders of magnitude. By comparing results from our study to studies of Si-H and C-H bonds in a-SiC:H [1] and SiC converted graphite [2], we suggest that this center is related to carbon dangling bonds created by the effusion of hydrogen during the dry heat-treatment. We will compare the activation energy for the hydrogen depassivation of our center with that found for other C-H and Si-H systems.

Dependence of the Sn0/2+ charge state on the Fermi level in semi-insulating CdTe

2007 ◽  
Vol 22 (11) ◽  
pp. 3249-3254 ◽  
Author(s):  
V. Babentsov ◽  
J. Franc ◽  
H. Elhadidy ◽  
A. Fauler ◽  
M. Fiederle ◽  
...  
Keyword(s):  
Fermi Level ◽  
Charge State ◽  
Strong Dependence ◽  
High Resistivity ◽  
Level Variation ◽  
Radiative Transitions ◽  
Deep Traps ◽  
First Time ◽  
Positively Charged

We explored the growth and characteristics of CdTe doped with Sn to heighten our understanding of the role of deep levels on electrical compensation and trapping. We demonstrated, for the first time, the strong dependence of the SnCd charge state on the Fermi-level variation (2–3kT) in high-resistivity CdTe. The concentration of deep traps for electrons was determined by the number of doubly positively charged Sn2+ atoms. Thermoelectric-effect spectroscopy and photovoltage measurements revealed the conversion of the SnCd defect from the electron SnCd2+ trap to the hole SnCd0 trap. The results agree well with the existence of a negative U-center in the SnCd0/2+ defect. We also showed that the neutral Sn defect is responsible for the near midgap C-band → bound hole radiative transitions band with a maximum at 0.76 eV.

scholarly journals Electron paramagnetic resonance in the research of defect formation and thermal processes during grinding of ZnO powders

2004 ◽  
Vol 36 (2) ◽  
pp. 65-72 ◽  
Author(s):  
M. Kakazey ◽  
M. Vlasova ◽  
M. Dominguez-Patiño ◽  
G. Dominguez-Patiño ◽  
T. Sreckovic ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Mechanical Treatment ◽  
Defect Formation ◽  
Thermal Processes ◽  
Defect Structures ◽  
Paramagnetic Centers ◽  
Paramagnetic Resonance ◽  
Zno Powders ◽  
Electron Paramagnetic

This work shows some possibilities for using electron paramagnetic resonance in an experimental study of the role of mechanothermal effects in the formation of defect structures in dispersed systems during prolonged mechanical treatment of ZnO powders. The use of EPR for this purpose is based on the known fact that initiation of a number of paramagnetic centers occurs during mechanical treatment of some materials. Such centers can serve as EPR-sondes of different thermal processes appearing during mechanical treatment of systems containing ZnO.

Compensation by deep levels in semi-insulating GaAs

1982 ◽  
Vol 60 (1) ◽  
pp. 35-40 ◽  
Author(s):  
B. A. Lombos ◽  
N. Yemenidjian ◽  
M. Averous
Keyword(s):  
Fermi Level ◽  
Multilevel Model ◽  
Deep Levels ◽  
High Resistivity ◽  
Spectrographic Analysis ◽  
Insulating Materials ◽  
Active Impurity ◽  
Source Mass ◽  
Insulating Properties

A multilevel model was developed to calculate the position of the Fermi level in GaAs. All the electrically-active impurity concentrations, indicated by spark source mass spectrographic analysis, were taken into account in the computation. The deduced semiconducting or semi-insulating properties are in agreement with the measured characteristics of the investigated crystals. It is shown that, in the case of the large gap semiconductors, only deep-lying impurity compensation results in high resistivity, semi-insulating materials.

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