scholarly journals Investigation of Crystal and Electronic Structures Features of Hf1-xTmxNiSn Semiconductor Solid Solution

2016 ◽  
Vol 17 (2) ◽  
pp. 212-221
Author(s):  
L.P. Romaka ◽  
P.-F. Rogl ◽  
A.M. Нoryn ◽  
V.Ya. Krayovskyy ◽  
Yu.V. Stadnyk ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid Solution ◽  
Electronic Structures ◽  
Energy State ◽  
Structural Defects ◽  
Crystallographic Site ◽  
Simultaneous Generation ◽  
Semiconductor Solid Solution ◽  
Crystal Structural

The features of structural, energy state and electrokinetic characteristics were investigated for Hf1‑xTmxNiSn solid solution in the range: T = 80 - 400 K, x = 0 - 0.40. It was confirmed partly disorder crystal structure of HfNiSn compound as a result of occupation in the 4a crystallographic site of Hf (5d26s2) atoms by Ni (3d84s2) ones up to ~ 1 % that generates in the crystal structural defects of donor nature. It was shown that introduction of Tm atoms ordered crystal structure (“healing” of structural defects). It was established mechanisms of simultaneous generation of structural defects as acceptors by substitution of Hf (5d26s2) by Tm (4f135d06s2) atoms, and the donor nature defects as a result of the appearance of vacancies in the Sn (4b) atoms sites, which determines the mechanisms of conductivity for Hf1-xTmxNiSn.

scholarly journals Features of Structural, Energy and Kinetic Characteristics of Hf1-xErxNiSn Solid Solution

2016 ◽  
Vol 17 (4) ◽  
pp. 552-558
Author(s):  
L.P. Romaka ◽  
P.-F. Rogl ◽  
A.M. Нoryn ◽  
V.V. Romaka ◽  
V.Ya. Krayovskyy ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid Solution ◽  
Structural Defects ◽  
Kinetic Characteristics ◽  
Crystallographic Site ◽  
Simultaneous Generation ◽  
Crystal Structural

1-xErxNiSn solid solution in the range: T = 80 – 400 K, x = 0 - 0.10. It was confirmed partly disorder crystal structure of HfNiSn compound as a result of occupation in the 4a crystallographic site of Hf (5d26s2) atoms by Ni (3d84s2) ones up to ~ 1 % that generates in the crystal structural defects of donor nature. It was shown that introduction of Er atoms ordered crystal structure (“healing” of structural defects). It was established mechanisms of simultaneous generation of structural defects as acceptors by substitution of Hf (5d26s2) by Er (4f125d06s2) atoms, and the donor nature defects as a result of the appearance of vacancies in the Sn (4b) atoms sites, which determines the mechanisms of conductivity for Hf1-xErxNiSn.

scholarly journals Synthesis, Structural, Electrical Transport and Energetic Characteristics of ZrNi1-хVxSn Solid Solution

2019 ◽  
Vol 20 (3) ◽  
pp. 275-281
Author(s):  
L. Romaka ◽  
Yu. Stadnyk ◽  
V.A. Romaka ◽  
A. Нoryn ◽  
I. Romaniv ◽  
...  
Keyword(s):  
Solid Solution ◽  
Fermi Level ◽  
Electrical Transport ◽  
Energy State ◽  
Structure Type ◽  
Structural Defects ◽  
Simultaneous Generation ◽  
Heusler Phase ◽  
Arc Melting ◽  
Donor And Acceptor

The samples of ZrNi1-хVxSn solid solution (x = 0 – 0.10) based on the ZrNiSn half-Heusler phase (MgAgAs structure type) were synthesized by direct arc-melting with homogenous annealing at 1073 K. The electrokinetic and energy state characteristics of the ZrNi1-хVxSn semiconducting solid solution were investigated in the temperature range T = 80 - 400 K. An analysis of behavior of the electrokinetic and energetic characteristics, in particular, the motion rate of the Fermi level, ΔεF/Δx for ZrNi1-хVxSn, allows to assume about the simultaneous generation of the structural defects of donor and acceptor nature in the crystal. The additional researches are required to establish the mechanisms of donor generation.

scholarly journals Features of Structural, Electrokinetic, and Energy State Characteristics of ZrNiSn1-xGax Solid Solution

2017 ◽  
Vol 18 (1) ◽  
pp. 41-48
Author(s):  
L.P. Romaka ◽  
A.M. Нoryn ◽  
Yu.V. Stadnyk ◽  
V.Ya. Krayovskyy ◽  
V.A. Romaka ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid Solution ◽  
Energy State ◽  
Impurity Band ◽  
Structural Defects ◽  
Acceptor Impurity ◽  
Acceptor Pair ◽  
Deep Donor ◽  
Temperature Ranges ◽  
Donor Acceptor

Features of structural, electrokinetic, and energy state characteristics of ZrNiSn1-xGax semiconductive solid solution were investigated in the temperature ranges Т = 80 - 400 K and х = 0 - 0.15. Disorder of crystal structure for n-ZrNiSn compound as a result of occupation of Zr (4d25s2) atoms in 4a sites by Ni (3d84s2) ones up to ~ 1 % was confirmed. It generated donor levels band ɛD1 in the band gap. It was shown that introduction of Ga (4s24p1) atoms by means of substitution of Sn (5s25p2) ones ordered crystal structure. In this case acceptor defects were generated in 4b sites and it created extended acceptor impurity band ɛА. It was suggested that with generation of acceptor structural defects the vacancies in the Sn (4b) atomic sites simultaneously generated donor defects and formed deep donor band ɛD2 (donor-acceptor pair took place).

scholarly journals Investigation of structural, thermodynamic and energy state characteristics of the ZrNi1-xRhxSn solid solution

2019 ◽  
Vol 19 (2) ◽  
pp. 151-158
Author(s):  
L.P. Romaka ◽  
Yu.V. Stadnyk ◽  
V.V. Romaka ◽  
P.-F. Rogl ◽  
V.A. Romaka ◽  
...  
Keyword(s):  
Solid Solution ◽  
Electrical Conductivity ◽  
Band Gap ◽  
Electronic Structures ◽  
Energy State ◽  
A Priori ◽  
Structural Defects ◽  
Maximum Efficiency ◽  
Deep Donor ◽  
Tetrahedral Voids

The peculiarities of crystal and electronic structures, thermodynamic and energy state characteristics of the ZrNi1-xRhxSn semiconductive solid solution were investigated. It has been shown that in the ZrNiSn compound simultaneously exist two types of structural defects of the donor nature which generate two donor bands with different ionization energy in the band gap: a) the donor band ɛD1, formed as a result of a partial, up to ~ 1%, occupation of 4a position of Zr atoms by Ni atoms (mechanism of “a priori doping”) and deep donor band ɛD2, formed as a result of partial occupation of the tetrahedral voids by Ni atoms (Vac). The substitution in 4c position of the Ni atoms by Rh ones in ZrNi1-xRhxSn generates structural defects of acceptor nature and creates an impurity acceptor band ɛA in the band gap, which, in addition to the existence of ɛD1 та ɛD2 donor bands, makes semiconductor highly doped and strongly compensated. The obtained results allow to understand the mechanisms of electrical conductivity of thermoelectric materials based on n-ZrNiSn and the ways of conscious optimization of their characteristics for obtaining the maximum efficiency of conversion of thermal energy into electric.

scholarly journals Investigation of Band Structure of ZrNiSn1-xGax Semiconductor Solid Solution

2017 ◽  
Vol 18 (2) ◽  
pp. 187-193
Author(s):  
L.P. Romaka ◽  
Yu.V. Stadnyk ◽  
V.V. Romaka ◽  
V.Ya. Krayovsky ◽  
P.-F. Rogl ◽  
...  
Keyword(s):  
Solid Solution ◽  
Band Structure ◽  
Fermi Level ◽  
Crystal Lattice ◽  
Crystallographic Site ◽  
Simultaneous Generation ◽  
Band Structure Calculations ◽  
Semiconductor Solid Solution ◽  
Donor Acceptor ◽  
Structure Calculations

The mechanism of simultaneous generation of donor-acceptor pairs in ZrNiSn1-xGax semiconductor solid solution is established. The modeled distribution of atoms in the crystal lattice of ZrNiSn1-xGax showed that the speed of movement of Fermi level εF, obtained from the band structure calculations is in agreement with experimental extracted from lnρ(1/T) dependencies. It is shown that with substitution of Sn (5s25p2) with Ga (4s24p1) atoms in 4b crystallographic site both acceptor and donor (vacancies in 4b site) defects are generated.

scholarly journals Investigation of structural, electrokinetic and energy state properties of the semiconductive Zr1-xVxNiSn solid solution

2019 ◽  
Vol 20 (1) ◽  
pp. 33-39
Author(s):  
V. Romaka ◽  
L. Romaka ◽  
Y. Stadnyk ◽  
A. Horyn ◽  
V. Krayovskyy ◽  
...  
Keyword(s):  
Solid Solution ◽  
Structural Change ◽  
Energy State ◽  
Energy Levels ◽  
Lattice Parameter ◽  
Structural Defects ◽  
Simultaneous Generation ◽  
Unknown Mechanism ◽  
Donor And Acceptor ◽  
Donor Acceptor

Structural, electrokinetic and energy state characteristics of the Zr1-xVxNiSn semiconductive solid solution (х=0–0.10) were investigated in the temperature interval 80–400 К. It was shown that doping of the ZrNiSn compound by V atoms (rV=0.134 nm) due to substitution of Zr (rZr=0.160 nm) results in increase of lattice parameter а(х) of Zr1-xVxNiSn indicating unforecast structural change. Based on analysis of the motion rate of the Fermi level ΔεF/Δх for Zr1-xVxNiSn in direction of the conduction band it was concluded about simultaneous generation of the structural defects of the donor and acceptor nature (donor-acceptor pairs) by unknown mechanism and creation of the corresponding energy levels in the band gap of the semiconductor.

scholarly journals Study of electrokinetic and magnetic properties of ZrNi1-xRhxSn semiconductive solid solution

2018 ◽  
Vol 19 (1) ◽  
pp. 21-28
Author(s):  
L.P. Romaka ◽  
Yu.V. Stadnyk ◽  
V.A. Romaka ◽  
A.M. Horyn ◽  
V.Ya. Krayovskyy
Keyword(s):  
Solid Solution ◽  
Magnetic Properties ◽  
Energy State ◽  
Charge Carriers ◽  
Structural Defects ◽  
Magnetic Characteristics ◽  
Main Charge ◽  
Deep Donor ◽  
Thermopower Coefficient ◽  
Donor Acceptor

The features of electrokinetic, energy state and magnetic characteristics of ZrNi1-xRhxSn semiconductive solid solution were investigated in the ranges: T = 80-400 K, x = 0-0.10. It was shown that substitution of Ni atoms (3d84s2) by Rh atoms (4d85s1) in the structure of ZrNiSn compound generated the structural defects with acceptor nature, and holes became the main charge carriers in the ZrNi1-xRhxSn at low temperature. Based on analysis of the motion rate of the Fermi level ΔεF/Δх in ZrNi1-xRhxSn to the valence band and change of sign of thermopower coefficient from positive to negative it was suggested that the structural defects of acceptor and donor natures were generated simultaneously (donor-acceptor pairs), and deep donor band ɛD2 was formed.

scholarly journals Investigation of V1-xTixFeSb Semiconductor Solid Solution. I. Peculiarities of Electrokinetic Characteristics

2015 ◽  
Vol 16 (1) ◽  
pp. 111-115
Author(s):  
V. А. Romaka ◽  
P. Rogl ◽  
Yu. V. Stadnyk ◽  
L. P. Romaka ◽  
R. O. Korzh ◽  
...  
Keyword(s):  
Solid Solution ◽  
Structural Defects ◽  
Unknown Mechanism ◽  
Semiconductor Solid Solution

The peculiarities of the temperature and concentration characteristics of resistivity and thermopower of V1-xTixFeSb semiconductor solid solution were investigated in the temperature and concentration ranges of T = 4.2 -400 K and Ті  ≈ 9.5·1019–3.6·1021 см-3 (х = 0.005 - 0.20), respectively. The existence of previously unknown mechanism for the generation of structural defects with donor nature which determined the conduction of n-VFeSb and V1-xTixFeSb was established. The acceptor type of structural defects generated in V1-xTixFeSb by substitution of V atoms by Ti ones was confirmed.

scholarly journals Features of Structural, Electrokinetic and Energy State Characteristics of V x+yCo1-ySb3 Skutterudite

2017 ◽  
Vol 18 (3) ◽  
pp. 328-333
Author(s):  
L.P. Romaka ◽  
Yu.V. Stadnyk ◽  
V.А. Romaka ◽  
A.M. Horyn
Keyword(s):  
Crystal Structure ◽  
Electrical Resistivity ◽  
Thermal Energy ◽  
Energy State ◽  
Electrical Energy ◽  
Structural Defects ◽  
Structure Characteristics ◽  
Impurity Atoms ◽  
Concentration Dependences ◽  
Thermopower Coefficient

The structure characteristics, temperature and concentration dependences of the electrical resistivity and the thermopower coefficient for the Vx+yCo1-ySb3 skutterudite were investigated in the ranges: T = 80 - 400 K, x = 0.02 - 0.20. It was shown that the introduction of V atoms into the structure of CoSb3 thermoelectric material was accompanied by an increase in the efficiency of conversion of thermal energy into electrical energy. It was established that the inversion in the sign of the thermopower coefficient for Vx+yCo1-ySb3 not observed for these concentrations of V impurity atoms. Based on the analysis of electrokinetic and energy state characteristics of Vx+yCo1-ySb3, it was assumed that the V (3d34s2) impurity atoms simultaneously replaced Co (3d74s2)atoms, generating structural defects of acceptor nature, and were located in the icosahedral voids of the crystal structure and generated donors. 

scholarly journals Investigation of Electronic Structure of Zr1-xVxNiSn Semiconductive Solid Solution

2019 ◽  
Vol 20 (2) ◽  
pp. 127-132
Author(s):  
Yu.V. Stadnyk ◽  
V.V. Romaka ◽  
V.A. Romaka ◽  
A.M. Нoryn ◽  
L.P. Romaka ◽  
...  
Keyword(s):  
Solid Solution ◽  
Electronic Structure ◽  
Electrical Properties ◽  
Band Gap ◽  
Electronic States ◽  
Structural Defects ◽  
Simultaneous Generation ◽  
Density Of Electronic States ◽  
Donor And Acceptor ◽  
Donor Acceptor

The peculiarities of electronic and crystal structures of Zr1-xVxNiSn (x = 0 - 0.10) semiconductive solid solution were investigated. To predict Fermi level εF behavior, band gap εg and electrokinetic characteristics of Zr1-xVxNiSn, the distribution of density of electronic states (DOS) was calculated. The mechanism of simultaneous generation of structural defects of donor and acceptor nature was determined based on the results of calculations of electronic structure and measurement of electrical properties of Zr1-xVxNiSn semiconductive solid solution. It was established that in the band gap of Zr1-xVxNiSn the energy states of the impurity donor εD2 and acceptor εA1 levels (donor-acceptor pairs) appear, which determine the mechanisms of conduction of semiconductor.

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