II-VI Compounds with Fe - New Family of Semimagnetic Semiconductors

1986 ◽  
Vol 89 ◽  
Author(s):  
Andrzej Mycielski
Keyword(s):  
Conduction Band ◽  
High Mobility ◽  
Free Carrier ◽  
Free Electrons ◽  
Energy Position ◽  
New Family ◽  
Carrier Scattering ◽  
Semimagnetic Semiconductors ◽  
Donor State ◽  
Substitutional Fe

AbstractSeveral experimental methods: absorption, photoemission and transport measurements were used to determine the energy position of substitutional Fe2+ (3d6) donor state in the band structure of the semimagnetic semiconductor Hg1-v-xCdvFexSe for 0≤v≤0.7 and v+x=l, and x≤0.15. For v≤0.40, Fe2+(3d6) level is a resonant donor located in the conduction band. For v=O (HgSe) we obtain 230 meV for the position of Fe2+(3d6) level with respect to the bottom of the conduction band which coincides with the position of the Fermi level for electron concentration N ≅5x1018 cm-3. Surprisingly, the mobility of free electrons (T∼4.2K) is abnormally high and the Dingle temperature measured in quantum magnetoresistivity oscillations (SdH effect) and magnetooptical measurements is abnormally low. Because of the Coulomb interaction between the ionized donors, at low T, there will appear some correlation of their positions. This may lead to a kind of “liquefying” of the system of ions and to its “crystallisation” (i.e. formation of a superlattice or hyperlattice of ionized donors) at even lower T. The space-ordering of ionized donors influences dramatically the free-carrier scattering and correspondingly explains the high mobility and low Dingle temperature. Finally, we shall also present some magnetic properties of these new semimagnetic materials.

scholarly journals Electron mobility dependence on neutron irradiation fluence in heavily irradiated silicon

2021 ◽  
Vol 61 (2) ◽  
Author(s):  
J.V. Vaitkus ◽  
A. Mekys ◽  
Š. Vaitekonis
Keyword(s):  
Neutron Irradiation ◽  
Electron Mobility ◽  
Carrier Mobility ◽  
Carrier Transport ◽  
Radiation Detector ◽  
Forward Bias ◽  
Free Carrier ◽  
Detector Efficiency ◽  
Applied Model ◽  
Carrier Scattering

An increase of neutron irradiation fluence caused a decrease of Si radiation detector efficiency that was exceptionally well seen at 1017 neutron/cm2 fluence when the observed I–V characteristic of p-n junction under forward bias and under reverse bias became similar. Therefore the investigation of free carrier mobility could be a key experiment to understand the change of heavily irradiated silicon. The electron mobility was investigated by magnetoresistance means in microstrip silicon samples at temperature range T = 200–276 K. The analysis included the free carrier scattering by phonons, ionized impurities, dipoles and clusters and a contribution of each process was found by fitting the mobility dependence on temperature. The analysis of experimental data clearly demonstrated that the applied model did not explain the mobility in the samples irradiated to the highest fluence. Therefore a new concept of carrier transport is needed, and, as a conclusion, it could be stated that Si irradiated above 1016 cm–2 fluence (and up to 1020 cm–2) is a disordered material with the clusters.

Low-temperature occupation of a donor state resonant with the conduction band inAl0.35Ga0.65As

1993 ◽  
Vol 48 (24) ◽  
pp. 17835-17840 ◽  
Author(s):  
A. Baraldi ◽  
F. Colonna ◽  
P. Frigeri ◽  
C. Ghezzi ◽  
A. Parisini ◽  
...  
Keyword(s):  
Low Temperature ◽  
Conduction Band ◽  
Donor State

Properties of Gainasp Alloys Investigated by Optically Detected Macnetic Resonance Techniques

1990 ◽  
Vol 216 ◽  
Author(s):  
C. Wetzel ◽  
B.K. Meyer ◽  
D. Grützmacher ◽  
P. Omling
Keyword(s):  
High Mobility ◽  
Chemical Vapor ◽  
Alloy System ◽  
Organic Chemical ◽  
Free Electrons ◽  
Quaternary Compound ◽  
Semiconductor Alloy ◽  
Device Applications ◽  
Metal Organic ◽  
Optically Detected

The quaternary GaxIn1−xAsyP1−y semiconductor alloy system has considerable importance for present day optoelectronic and microwave device applications. For state of the art high mobility samples grown by metal organic chemical vapor deposition (MOVPE) there are few experimental techniques which both can asess band structure related properties (effective mass m*, g-values of free electrons) and impurity related properties (luminescence, mobility and lifetimes). In this paper we compare optical and transport properties of the quaternary compound GaxIn1−xAsyP1−y, (x=0.47,y-l; x=0.42,y=0.92; x=0.28,y=0.61; x=0.12,y=0.34) lattice matched to*{nP by optically detected magnetic resonance techniques.

Equilibrium model for the interpretation of the conduction properties of metal–ammonia solutions

1977 ◽  
Vol 55 (11) ◽  
pp. 2211-2216 ◽  
Author(s):  
S. Hahne ◽  
P. Krebs ◽  
U. Schindewolf
Keyword(s):  
Electrical Conductivity ◽  
Pressure Range ◽  
High Mobility ◽  
Solvation Number ◽  
Free Electrons ◽  
Solvated Electrons ◽  
Entire Concentration Range ◽  
Pressure Coefficients ◽  
Temperature And Pressure ◽  
Conduction Properties

The electrical conductivity of metal–ammonia solutions can be described by an equilibrium of solvated electrons of low mobility and of free electrons of high mobility. With proper choice of the equilibrium constant and its temperature and pressure dependence and of the solvation number of the solvated species the experimental conductivities can be matched in the temperature and pressure range from 240 to 420 K and up to 1000 bar over the entire concentration range from 0.1 mol/ℓ to saturation, also fitting the extrema of the temperature and pressure coefficients of the conductivity around 1 mol/ℓ.

Free‐carrier induced saturation of the Faraday rotation in semimagnetic semiconductors

1995 ◽  
Vol 66 (16) ◽  
pp. 2043-2045 ◽  
Author(s):  
S. Hugonnard‐Bruyère ◽  
C. Buss ◽  
R. Frey ◽  
C. Flytzanis
Keyword(s):  
Faraday Rotation ◽  
Free Carrier ◽  
Semimagnetic Semiconductors

The Density of States in a-Si:C:H Revealed by Electrophotography

1993 ◽  
Vol 297 ◽  
Author(s):  
R.A.C.M.M. Van Swaaij ◽  
W.P.M. Willems ◽  
J. Bezemer ◽  
M.B. Von Der Linden ◽  
W.F. Van Der Weg
Keyword(s):  
Conduction Band ◽  
Density Of States ◽  
Carbon Concentration ◽  
Band Edge ◽  
Conduction Band Edge ◽  
Temperature Dependent ◽  
Energy Position ◽  
A Value ◽  
Dark Decay ◽  
Bulk Space

Electrophotographic dark decay measurements have been used to determine the surface density of states (SDOS) of a-Si:C:H. Injection of trapped charge from these deep states into the conduction band governs the dark discharge of a photoconductor, provided bulk generation and bulk space charge are negligible. It is found that the SDOS profiles peak around 0.60 eV below the conduction band for materials with different carbon concentration. This observation implies that the energy position of these states is fixed with respect to the conduction band edge, even though the optical band gap of these materials increases with increasing carbon concentration. The nature of these states may be ascribed to D− states, whose density is strongly enhanced by filling D° states when the material is charged negatively. Furthermore, we observed that the SDOS around 0.60 eV below the conduction band edge is approximately the same for materials with up to 8 at.% carbon. From temperature dependent measurements a value of 2·108 s−1 was obtained for the attempt-to-escape frequency.

Self-Consistent Subband Calculations of AlxGa1-xN/(AlN)/GaN-Based High Electron Mobility Transistor

2010 ◽  
Vol 159 ◽  
pp. 342-347 ◽  
Author(s):  
T.R. Lenka ◽  
A.K. Panda
Keyword(s):  
Conduction Band ◽  
Electron Mobility ◽  
High Mobility ◽  
High Electron Mobility Transistor ◽  
High Electron ◽  
High Electron Mobility ◽  
Self Consistent ◽  
Band Profile ◽  
Alloy Disorder ◽  
Rf Performance

In this paper, there is an attempt to present the two dimensional electron gas (2DEG) transport characteristics of AlxGa1-xN/(AlN)/GaN-based High Electron Mobility Transistor (HEMT) using a self-consistent numerical method for calculating the conduction-band profile and subband structure. The subband calculations take into account the piezoelectric and spontaneous polarization effects and the Hartree and exchange-correlation interaction. Here the dependency of conduction band profile, subband energies, 2DEG sheet concentration and sheet resistance on various Al mole fractions of AlxGa1-xN barrier layer are presented by incorporating simulation as well as available experimental data. Introduction of very thin binary AlN layer at the heterojunction of AlxGa1-xN/GaN resulting high mobility at high sheet charge densities by increasing the effective and decreasing alloy disorder scattering. Devices based on this structure exhibit good DC and RF performance as an increase of . Owing to high 2DEG density , the proposed device leads to operate in microwave and millimeter wave applications.

Free Carrier Scattering in Hg0.77Mn0.23Se at Low Temperatures

1991 ◽  
Vol 168 (2) ◽  
pp. K103-K107 ◽  
Author(s):  
O. Žižić ◽  
Z. V. Popović ◽  
A. Milutinović ◽  
V. A. Kulbachinskii
Keyword(s):  
Low Temperatures ◽  
Free Carrier ◽  
Carrier Scattering
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