Investigation of Thermoelectric Properties of P-Type GaN Thin Films

2015 ◽  
Vol 1774 ◽  
pp. 13-18
Author(s):  
Bahadir Kucukgok ◽  
Babar Hussain ◽  
Chuanle Zhou ◽  
Ian T. Ferguson ◽  
Na Lu
Keyword(s):  
High Temperature ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Room Temperature ◽  
Mechanical Stability ◽  
Gradient Methods ◽  
Chemical Vapor ◽  
High Seebeck Coefficient ◽  
P Type ◽  
Bipolar Conduction

ABSTRACTGaN and its alloys are promising candidates for high temperature thermoelectric (TE) materials due to their high Seebeck coefficient and high thermal and mechanical stability. Moreover, these materials can overcome the toxicity concern of current Te-based TE materials, such as Bi2Te3 and PbTe. These materials have recently shown a higher Seebeck coefficient than that of SiGe in high temperature region because their large bandgap characteristic eliminates the bipolar conduction. In this study, we report the room temperature thermoelectric properties of p-type Mg doped GaN, grown by metalorganic chemical vapor deposition (MOCVD) on sapphire substrate with various carrier concentrations. Undoped and n-type GaN are also incorporated with p-type GaN films to make comparison. The structural, optical, electrical, and thermal properties of the samples were examined by X-ray diffraction, photoluminescence, van der Pauw hall-effect, and thermal gradient methods, respectively. The Seebeck coefficient ranging from 710-900µV/K at room temperature of Mg: GaN were observed, which further indicated their potential TE applications.

Thermoelectric Properties of Semiconducting Intermetallic Compounds: FeGa3and RuGa3

2003 ◽  
Vol 793 ◽  
Author(s):  
Y. Amagai ◽  
A. Yamamoto ◽  
C. H. Lee ◽  
H. Takazawa ◽  
T. Noguchi ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
High Temperature ◽  
Seebeck Coefficient ◽  
Transport Properties ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
High Seebeck Coefficient

ABSTRACTWe report transport properties of polycrystalline TMGa3(TM = Fe and Ru) compounds in the temperature range 313K<T<973K. These compounds exhibit semiconductorlike behavior with relatively high Seebeck coefficient, electrical resistivity, and Hall carrier concentrations at room temperature in the range of 1017- 1018cm−3. Seebeck coefficient measurements reveal that FeGa3isn-type material, while the Seebeck coefficient of RuGa3changes signs rapidly from large positive values to large negative values around 450K. The thermal conductivity of these compounds is estimated to be 3.5Wm−1K−1at room temperature and decreased to 2.5Wm−1K−1for FeGa3and 2.0Wm−1K−1for RuGa3at high temperature. The resulting thermoelectric figure of merit,ZT, at 945K for RuGa3reaches 0.18.

THERMOELECTRIC PROPERTIES OF Ti-DOPED SiC/TiCx COMPOSITE SYNTHESIZED BY TPPP METHOD

2000 ◽  
Vol 14 (04) ◽  
pp. 131-138 ◽  
Author(s):  
HONG CHEN ◽  
YUZHE YIN ◽  
YUANJIN HE
Keyword(s):  
Solid Solution ◽  
High Temperature ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Room Temperature ◽  
Lattice Parameter ◽  
Interstitial Impurities ◽  
Plastic Phase ◽  
Phase Process

To improve thermoelectric properties, we attempt to dope Ti into SiC-based composite by transient plastic phase process (TPPP) method. The final result is composed of the functional phase SiC and the reinforcement phases TiC x and TiSi 2. The process of doping is the diffusion of Ti in TiC x solid–solution into SiC grain at high temperature. When the initial SiC is α-type of 5 μm size, the Seebeck coefficient S is less than 10 μV/K at room temperature. SEM photograph shows the reason being that doping is very weak. We change the initial SiC to the β-type of 90 nm size to aid doping. It is observed that S can be significantly improved to 46.3 μV/K at room temperature. When the temperature rises, the improvement is even greater. Measurements of the lattice parameter of β- SiC show that the parameter parallel to the Si–C layer is almost unchanged and the parameter perpendicular to the Si–C layer increases by about 0.48%, which demonstrated that Ti has been successfully doped into the SiC grain and exists as interstitial impurities.

Synthesis and High Temperature Thermoelectric Properties of Alkaline-Earth Metal Hexaborides MB6 (M=Ca, Sr, Ba)

2003 ◽  
Vol 793 ◽  
Author(s):  
Masatoshi Takeda ◽  
Yosuke Kurita ◽  
Keisuke Yokoyama ◽  
Takahiro Miura ◽  
Tsuneo Suzuki ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
High Temperature ◽  
Seebeck Coefficient ◽  
Carrier Concentration ◽  
Thermoelectric Properties ◽  
Alkaline Earth ◽  
Earth Metal ◽  
Thermoelectric Device ◽  
Alloying Effect ◽  
P Type

ABSTRACTPolycrystalline alkaline-earth hexaborides (MB6: M =Ca, Sr, Ba) were synthesized and their thermoelectric and transport properties were examined to discuss their possibility as high temperature thermoelectric materials. Hall measurements showed that carrier concentration of the BaB6 was the highest among the three hexaborides and that of CaB6 was the lowest. Substitution of part of the alkaline earth metals with one of the others changed the carrier concentration of the hexaboride. As the carrier concentration increased, Seebeck coefficient increased and electrical conductivity decreased. These results suggest that the thermoelectric properties of the divalent hexaborides depend largely on the carrier concentration, and optimum carrier concentration which gives maximum power factor was estimated to be approximately 2x1026 m−3. Consequently, such a substitution enables us to control Seebeck coefficient and electrical conductivity of the hexaborides, and will also be effective to reduce the lattice heat conduction due to the alloying effect. A thermoelectric device was fabricated using SrB6 and boron carbide thin films as n-type and p-type elements, respectively. To the best of our knowledge, this is the first demonstration of a thermoelectric device composed of only boron-rich solids.

Synthesis, Crystal Structure and Thermoelectric Properties of β-K2Bi8Se13 Solid Solutions

2003 ◽  
Vol 793 ◽  
Author(s):  
Theodora Kyratsi ◽  
Duck Young Chung ◽  
Jeff S. Dyck ◽  
Ctirad Uher ◽  
Sangeeta Lal ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid Solution ◽  
High Temperature ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Band Gaps ◽  
Solid Solution Series ◽  
Type K ◽  
Type Character ◽  
P Type

ABSTRACTSolid solution series of the type K2Bi8-xSbxSe13, K2-xRbxBi8Se13 as well as K2Bi8Se13-xSx were prepared and the distribution of the atoms (Bi/Sb, K/Rb and Se/S) on different crystallographic sites, the band gaps and their thermoelectric properties were studied. The distribution Se/S appears to be more uniform than the distribution of the Sb and Rb atoms in the β-K2Bi8Se13 structure that shows preference in specific sites in the lattice. Band gap is mainly affected by Sb and S substitution. Seebeck coefficient measurements showed n-type character for of all Se/S members. In the Bi/Sb series an enhancement of p-type character was observed. The thermoelectric performance as well as preliminary high temperature measurements suggest the potential of these materials for high temperature applications.

High-Temperature Thermoelectric Properties of Silicon Boride Ceramics as a Smart Material

1999 ◽  
Vol 604 ◽  
Author(s):  
Noriyuki Takashima ◽  
Yasuo Azuma ◽  
Jun-Ichi Matsushita
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
High Temperature ◽  
Seebeck Coefficient ◽  
Relative Density ◽  
Thermoelectric Properties ◽  
Room Temperature ◽  
Sintering Temperature ◽  
Smart Material ◽  
Increasing Temperature

AbstractSeveral silicon boride phases such as SiB4, SiB6, SiB6-x, SiB6+x, and Si11B31, were previously reported. Among them, SiB6has proved to be a potentially useful material because of its excellent electrical conductivity, high degree of hardness, moderate melting point, and low specific gravity. The sintering conditions and thermoelectric properties of silicon boride (SiB6) ceramics produced by hot pressing were investigated in order to determine the suitability of this material for high-temperature thermoelectric applications as a smart material. The relative density increased with increasing sintering temperature. With a sintering temperature of 1923 K, a sintered body having a relative density of more than 99% was obtained. X-ray diffraction analysis showed no crystalline phase other than SiB6 in the sintered body. The specimens were prepared for measurement of the electrical conductivity and Seebeck coefficient by the D.C. four-terminal method. The thermal conductivity of SiB6 was obtained by calculation from the thermal diffusivity and specific heat capacity of the specimen. The electrical conductivity of SiB6 increased with increasing temperature. The electrical conductivity of the polycrystalline SiB6 (99% dense) was 0.5 to 1.1 × 103 S/m at 298 to 1273 K. The thermal conductivity decreased with increasing temperature in the range of room temperature to 1273 K. The thermal conductivity was 9.1 to 2.5 W/mK in the range of room temperature to 1273 K. The Seebeck coefficient of SiB6 increased with increasing temperature. The Seebeck coefficient of SiB6 was 140 × 10−6 V/K at 1273 K. The figure of merit Z of SiB6 increased with increasing temperature. The Z of SiB6 reached 8.1 × 10−6/K at 1273 K. The ZT value is useful to evaluate the ability of thermoelectric materials. The ZT value reached 0.01 at 1273 K. Based on the results, SiB6 showed very good thermoelectric material characteristics at high temperature.

Thermoelectric Properties of Sn2+-Substituted CuFeO2 Delafossite-Oxide

2013 ◽  
Vol 802 ◽  
pp. 17-21 ◽  
Author(s):  
Chesta Ruttanapun ◽  
Phumin Jindajitawat ◽  
Warawoot Thowladda ◽  
Worakarn Neeyakorn ◽  
Chanchana Thanachayanont ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Temperature ◽  
Solid State ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Positive Sign ◽  
Prediction Formula ◽  
Mixed Valency ◽  
Maximum Power Factor ◽  
P Type

This study aims to investigate the effect of the Sn2+-substituted into the CuFeO2delafossite on thermoelectric properties in the Sn content of x = 0.03, 0.05. The CuFe1−xSnxO2samples were synthesized by solid state reaction. The crystal structure was characterized by XRD, TGA, XPS and the thermoelectric properties were measured in the range of 300 to 960 K. The Seebeck coefficient display positive sign in all temperature range and the XPS show the stable Sn+2state as confirming the Sn-doped CuFeO2playing p-type conductor. The Sn2+-substituted supports the mixed valency Fe3+/Fe4+state in transition octahedral oxide of FeO6layer enhancing Seebeck coefficient. The high Seebeck are appeared in content of x=0.03 which are 280 to 340 µV/K in the range of 300 to 800 K. The experimental Seebeck corresponds to the prediction formula at high temperature. Totally, the maximum Power Factor is 2.30×10−4W/mK2occurring in the CuFe0.95Sn0.05O2at 860 K which is higher than that value of the undoped-CuFeO2in 4 times. These support that the Sn-substituted CuFeO2delafossite enhancing thermoelectric properties.

High Thermoelectric Performance of p-Type Bi0.5Sb1.5Te3+xTe Crystals Prepared via Gradient Freezing

2012 ◽  
Vol 621 ◽  
pp. 167-171
Author(s):  
Tao Hua Liang ◽  
Shi Qing Yang ◽  
Zhi Chen ◽  
Qing Xue Yang
Keyword(s):  
Thermal Conductivity ◽  
Seebeck Coefficient ◽  
Carrier Concentration ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Thermoelectric Performance ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
P Type

p-type Bi0.5Sb1.5Te3+xTe thermoelectric crystals with various percentages of Te (x = 0.00 wt.%–3.00 wt.%) excess were prepared by the gradient freeze method. By doping with different Te contents, anti-site defects, Te vacancies and hole carrier concentrations were controlled. The Seebeck coefficient, resistivity, thermal conductivity, carrier concentration, and mobility were measured. The relationships between the Te content and thermoelectric properties were investigated in detail. The results suggested that the thermoelectric figure of merit ZT of the Bi0.5Sb1.5Te3+0.09wt.% crystals was 1.36 near room temperature, the optimum carrier concentration was 1.25 × 1019 cm-3, and the mobility was 1480 cm2 V-1 S-1, respectively.

The Influence of Silicon Dopant and Processing on Thermoelectric Properties of B4C Ceramics

1998 ◽  
Vol 545 ◽  
Author(s):  
Ke-Feng Cai ◽  
Ce-Wen Nan ◽  
Xin-Min Min
Keyword(s):  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Hot Pressing ◽  
Figure Of Merit ◽  
Room Temperature ◽  
A Value ◽  
Si Doped

AbstractB4C ceramics doped with various content of Si (0 to 2.03 at%) are prepared via hot pressing. The composition and microstructure of the ceramics are characterized by means of XRD and EPMA. Their electrical conductivity and Seebeck coefficient of the samples are measured from room temperature up to 1500K. The electrical conductivity increases with temperature, and more rapidly after 1300K; the Seebeck coefficient of the ceramics also increases with temperature and rises to a value of about 320μVK−1. The value of the figure of merit of Si-doped B4C rises to about 4 × 10−4K−1 at 1500K.

High-temperature thermoelectric properties of p-type skutterudites Ba0.15Yb x Co3FeSb12 and Yb y Co3FeSb9As3

2014 ◽  
Vol 50 (1) ◽  
pp. 34-39 ◽  
Author(s):  
Yongkwan Dong ◽  
Pooja Puneet ◽  
Terry M. Tritt ◽  
George S. Nolas
Keyword(s):  
High Temperature ◽  
Thermoelectric Properties ◽  
P Type

scholarly journals Effect of Microwave Processing and Glass Inclusions on Thermoelectric Properties of P-Type Bismuth Antimony Telluride Alloys for Wearable Applications

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4524
Author(s):  
Amin Nozariasbmarz ◽  
Daryoosh Vashaee
Keyword(s):  
Seebeck Coefficient ◽  
Thermoelectric Materials ◽  
Room Temperature ◽  
Electronic Devices ◽  
Microwave Processing ◽  
Glass Inclusion ◽  
Wearable Electronic ◽  
P Type ◽  
Wearable Electronic Devices ◽  
Body Heat

Depending on the application of bismuth telluride thermoelectric materials in cooling, waste heat recovery, or wearable electronics, their material properties, and geometrical dimensions should be designed to optimize their performance. Recently, thermoelectric materials have gained a lot of interest in wearable electronic devices for body heat harvesting and cooling purposes. For efficient wearable electronic devices, thermoelectric materials with optimum properties, i.e., low thermal conductivity, high Seebeck coefficient, and high thermoelectric figure-of-merit (zT) at room temperature, are demanded. In this paper, we investigate the effect of glass inclusion, microwave processing, and annealing on the synthesis of high-performance p-type (BixSb1−x)2Te3 nanocomposites, optimized specially for body heat harvesting and body cooling applications. Our results show that glass inclusion could enhance the room temperature Seebeck coefficient by more than 10% while maintaining zT the same. Moreover, the combination of microwave radiation and post-annealing enables a 25% enhancement of zT at room temperature. A thermoelectric generator wristband, made of the developed materials, generates 300 μW power and 323 mV voltage when connected to the human body. Consequently, MW processing provides a new and effective way of synthesizing p-type (BixSb1−x)2Te3 alloys with optimum transport properties.

Sign in / Sign up

Export Citation Format

Share Document