Effects of potential barrier height and its fluctuations at grain boundaries on thermoelectric properties of polycrystalline semiconductors

2013 ◽  
Vol 114 (5) ◽  
pp. 053707 ◽  
Author(s):  
Y. Kajikawa
Keyword(s):  
Grain Boundaries ◽  
Barrier Height ◽  
Potential Barrier ◽  
Thermoelectric Properties ◽  
Potential Barrier Height ◽  
Polycrystalline Semiconductors

scholarly journals Effects of Charge Compensation on Colossal Permittivity and Electrical Properties of Grain Boundary of CaCu3Ti4O12 Ceramics Substituted by Al3+ and Ta5+/Nb5+

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3294
Author(s):  
Jakkree Boonlakhorn ◽  
Jedsada Manyam ◽  
Pornjuk Srepusharawoot ◽  
Sriprajak Krongsuk ◽  
Prasit Thongbai
Keyword(s):  
Dielectric Properties ◽  
Electrical Properties ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Barrier Height ◽  
Potential Barrier ◽  
Charge Compensation ◽  
Solid State Reaction Method ◽  
Wide Frequency Range ◽  
Potential Barrier Height

The effects of charge compensation on dielectric and electrical properties of CaCu3Ti4-x(Al1/2Ta1/4Nb1/4)xO12 ceramics (x = 0−0.05) prepared by a solid-state reaction method were studied based on the configuration of defect dipoles. A single phase of CaCu3Ti4O12 was observed in all ceramics with a slight change in lattice parameters. The mean grain size of CaCu3Ti4-x(Al1/2Ta1/4Nb1/4)xO12 ceramics was slightly smaller than that of the undoped ceramic. The dielectric loss tangent can be reduced by a factor of 13 (tanδ ~0.017), while the dielectric permittivity was higher than 104 over a wide frequency range. Impedance spectroscopy showed that the significant decrease in tanδ was attributed to the highly increased resistance of the grain boundary by two orders of magnitude. The DFT calculation showed that the preferential sites of Al and Nb/Ta were closed together in the Ti sites, forming self-charge compensation, and resulting in the enhanced potential barrier height at the grain boundary. Therefore, the improved dielectric properties of CaCu3Ti4-x(Al1/2Ta1/4Nb1/4)xO12 ceramics associated with the enhanced electrical properties of grain boundaries. In addition, the non-Ohmic properties were also improved. Characterization of the grain boundaries under a DC bias showed the reduction of potential barrier height at the grain boundary. The overall results indicated that the origin of the colossal dielectric properties was caused by the internal barrier layer capacitor structure, in which the Schottky barriers at the grain boundaries were formed.

scholarly journals Potential barrier height at the grain boundaries of a poly-silicon nanowire

2015 ◽  
Vol 26 (35) ◽  
pp. 355201 ◽  
Author(s):  
Assaf Shamir ◽  
Iddo Amit ◽  
Danny Englander ◽  
Dror Horvitz ◽  
Yossi Rosenwaks
Keyword(s):  
Grain Boundaries ◽  
Barrier Height ◽  
Potential Barrier ◽  
Silicon Nanowire ◽  
Potential Barrier Height ◽  
Poly Silicon

The potential barrier height for a Jahn-Teller center

2004 ◽  
Vol 99 (1) ◽  
pp. 189-196 ◽  
Author(s):  
V. N. Vasyukov ◽  
A. D. Prokhorov ◽  
V. P. D’yakonov ◽  
H. Szymczak
Keyword(s):  
Barrier Height ◽  
Potential Barrier ◽  
Potential Barrier Height ◽  
Jahn Teller

Potential Barrier Height Analysis of AlGaInP Multi-Quantum Barrier (MQB)

1990 ◽  
Vol 29 (Part 2, No. 11) ◽  
pp. L1977-L1980 ◽  
Author(s):  
Takeshi Takagi ◽  
Fumio Koyama ◽  
Kenichi Iga
Keyword(s):  
Barrier Height ◽  
Potential Barrier ◽  
Potential Barrier Height

scholarly journals Low potential barrier height effects in magnetic tunneling junctions

2007 ◽  
Vol 76 (21) ◽  
Author(s):  
E. S. Cruz de Gracia ◽  
L. S. Dorneles ◽  
L. F. Schelp ◽  
S. R. Teixeira ◽  
M. N. Baibich
Keyword(s):  
Barrier Height ◽  
Potential Barrier ◽  
Potential Barrier Height ◽  
Tunneling Junctions ◽  
Magnetic Tunneling Junctions ◽  
Magnetic Tunneling

Potential Barrier Height Effects on the Intrasubband and Intersubband Quasi-One-Dimensional Plasmons

1997 ◽  
Vol 11 (09n10) ◽  
pp. 441-451 ◽  
Author(s):  
Paulo César Miranda Machado ◽  
Francisco A. P. Osório ◽  
A. Newton Borges
Keyword(s):  
Barrier Height ◽  
Potential Barrier ◽  
Random Phase Approximation ◽  
Rectangular Cross Section ◽  
Pair Correlation ◽  
Random Phase ◽  
Potential Effect ◽  
Potential Barrier Height ◽  
Energy Structure ◽  
Barrier Heights

The effects of the potential barrier height on the collective excitations of a electron gas confined in a GaAs-AlxGa1-xAs quantum wire of rectangular cross-section are investigated theoretically. For several potential barrier heights, we calculated the plasmon energy, structure factor and pair-correlation function, within the Random-Phase Approximation regime, considering a three-subband model with only the lowest subband populated by electrons. We verified that the intersubband plasmon is more sensitive to the potential barrier height variation than the intrasubband plasmon. We also observed that the confining potential effect decreases with the increasing of the wire-width.

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