Carrier Pocket Engineering to Design Superior Thermoelectric Materials Using GaAs/AlAs Superlattices

1998 ◽  
Vol 545 ◽  
Author(s):  
T. Koga ◽  
X. Sun ◽  
S. B. Cronin ◽  
M. S. Dresselhaus
Keyword(s):  
Quantum Wells ◽  
Figure Of Merit ◽  
Growth Direction ◽  
Present Calculation ◽  
High Symmetry ◽  
Thermoelectric Figure ◽  
Bulk Gaas ◽  
Basic Model ◽  
Short Period ◽  
Superlattice Period

AbstractA large enhancement in the thermoelectric figure of merit for the whole superlattice, Z3DT, is predicted for short period GaAs/AlAs superlattices relative to bulk GaAs. Various superlattice parameters (superlattice growth direction, superlattice period and layer thicknesses) are explored to optimize Z3DT, including quantum wells formed at various high symmetry points in the Brillouin zone. The highest room temperature Z3DT obtained in the present calculation is 0.41 at the optimum carrier concentration for either (001) or (111) oriented GaAs(20 Å)/AIAs(20 Å) superlattices, which is about 50 times greater than the corresponding ZT for bulk GaAs obtained using the same basic model.

Magnetooptical Studies of Acceptors Confined in GaAs/AIGaAs Quantum Wells

1993 ◽  
Vol 325 ◽  
Author(s):  
P.O. Holtz ◽  
Q.X. Zhao ◽  
B. Monemar ◽  
A. Pasquarello ◽  
M. Sundaram ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Quantum Wells ◽  
Ground State ◽  
Energy Levels ◽  
Zeeman Splitting ◽  
Growth Direction ◽  
Bulk Gaas ◽  
Theoretical Predictions ◽  
Resonant Raman ◽  
The Magnetic Field

AbstractMagnetooptical studies have been performed on the shallow Be acceptor confined in the central region of narrow GaAs/AlGaAs quantum wells (QWs) with the magnetic field along the growth direction. The magnetic field dependence of the acceptor transition between the 1S(Г6) hh-like ground state and the excited hh-like 2S(Г6) state has been investigated by means of two independent techniques: Two-hole transitions of the acceptor bound exciton (BE) and resonant Raman scattering. The 1S(Г6) – 2S(Г6) transition energy as a function of the magnetic field has been measured for central acceptors in QWs of widths in the range 50 – 150 Å. The energy levels for the 1S ground states and 2S excited states of the confined acceptor with a magnetic field as a perturbation have also been calculated. These calculations predict a larger splitting between the mj=+3/2 and mj=−3/2 components of the acceptor 1S(Г6) ground state in comparison with the corresponding splitting of the excited 2S(Г6) state. The experimental results are in good agreement with the theoretical predictions derived without any fitting parameters. Furthermore, the Zeeman splitting of the acceptor BE emission has been measured and it is concluded that the J = 5/2 BE state is lowest in energy, similar to shallow acceptor BEs in bulk GaAs.

Extraordinary thermoelectric performance of NaBaBi with degenerate and highly non-parabolic bands compared to LiBaSb and Bi2Te3

2021 ◽  
Author(s):  
Enamul Haque
Keyword(s):  
Fermi Level ◽  
Figure Of Merit ◽  
Thermoelectric Performance ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure

This article reports the extraordinary thermoelectric figure of merit (ZT) of NaBaBi: degenerate bands, instead of the valley degeneracy of Bi2Te3, highly non-parabolic bands, and low DOS near the Fermi level of NaBaBi lead to an extraordinary ZTisotropic ≈ 1.60 at 350 K.

Influence of multi-sintering on the thermoelectric properties of Bi2Sr2Co2Oy ceramics

2019 ◽  
Vol 34 (02) ◽  
pp. 2050019 ◽  
Author(s):  
Y. Zhang ◽  
M. M. Fan ◽  
C. C. Ruan ◽  
Y. W. Zhang ◽  
X.-J. Li ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Phonon Scattering ◽  
Sintered Sample ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
The Third ◽  
Ceramic Samples ◽  
Optimum Formula

[Formula: see text] ceramic samples have a structure similar to phonon glass electronic crystals, and their thermoelectric properties can be effectively adjusted through repeated grinding and sintering. The results show that multi-sintering can make their grain refined and increase their grain boundary, which will effectively increase density and phonon scattering. Finally, multi-sintering can reduce the resistivity and thermal conductivity, thus obviously improve thermoelectric figure of merit [Formula: see text] of [Formula: see text]. The optimum [Formula: see text] value of 0.26 is achieved at 923 K by the third sintered sample.

Assignments of transitions in optically-pumped NMR of GaAs/AlGaAs quantum wells on a bulk GaAs substrate

2014 ◽  
Vol 90 (12) ◽  
Author(s):  
E. L. Sesti ◽  
D. D. Wheeler ◽  
S. E. Hayes ◽  
D. Saha ◽  
G. D. Sanders ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Gaas Substrate ◽  
Optically Pumped ◽  
Bulk Gaas ◽  
Optically Pumped Nmr

A strategy for boosting the thermoelectric performance of famatinite Cu3SbS4

2020 ◽  
Vol 22 (4) ◽  
pp. 2081-2086 ◽  
Author(s):  
Taiki Tanishita ◽  
Koichiro Suekuni ◽  
Hirotaka Nishiate ◽  
Chul-Ho Lee ◽  
Michitaka Ohtaki
Keyword(s):  
Figure Of Merit ◽  
Thermoelectric Performance ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Co Substitution

Co-substitution of Ge and P for Sb in Cu3SbS4 famatinite boosted dimensionless thermoelectric figure of merit.

Thermoelectric Properties of n-Type 90% Bi2Te3+10%Bi2Se3 Thermoelectric Materials Produced by Melt Spinning Method and Sintering

2007 ◽  
Vol 534-536 ◽  
pp. 161-164 ◽  
Author(s):  
Taek Soo Kim ◽  
Byong Sun Chun
Keyword(s):  
Solid Solutions ◽  
Thermoelectric Materials ◽  
Figure Of Merit ◽  
Melt Spinning ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Thermoelectric Figure Of Merit ◽  
Vacuum Sintering ◽  
Thermoelectric Figure ◽  
Sintering Processes

N-type Bi2Te3-Sb2Te3 solid solutions doped with CdCl2 was prepared by melt spinning, crushing and vacuum sintering processes. Microstructure, bending strength and thermoelectric property were investigated as a function of the doping quantity from 0.03wt.% to 0.10wt.% and sintering temperature from 400oC to 500oC, and finally compared with those of conventionally fabricated alloys. The alloy showed a good structural homogeneity as well as bending strength of 3.88Kgf/mm2. The highest thermoelectric figure of merit was obtained by doping 0.03wt.% and sintering at 500oC.

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