Thermoelectric Micro-Cooler of Bismuth Telluride Thin Films

2007 ◽  
Author(s):  
Koji Miyazaki ◽  
Jun-Ichiro Kurosaki ◽  
Masayuki Takashiri ◽  
Bertrand Lenoir ◽  
Hiroshi Tsukamoto
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Thermal Conductivity ◽  
Thermoelectric Power ◽  
Bismuth Telluride ◽  
Figure Of Merit ◽  
Flash Evaporation ◽  
3Ω Method ◽  
Fine Powders ◽  
P Type

In this study, we fabricated bismuth-telluride thin films and their in-plane thermoelectric micro-coolers (4mm×4mm) by using the flash evaporation method. We prepared fine powders of Bi2.0Te2.7Se0.3 (n-type) and Bi0.4Te3.0Sb1.6 (p-type). The thermoelectric properties of as-grown thin films are lower than those of bulk materials. Therefore the as-grown thin films were annealed in hydrogen at atmospheric pressure for 1 hour in a temperature range of 200 to 400°C. By optimizing the annealing temperature, thin films with high thermoelectric power factors of 8.8 μW/(cm·K2) in n-type and 13.8 μW/(cm·K2) in p-type are obtained. To evaluate the figure of merit of the thin film, the thermal conductivity of the n-type thin film is measured by the 3ω method. The thin film annealed at 200 °C exhibited a cross-plane thermal conductivity of 1.2 W/(m·K). Micro-coolers of flash-evaporated bismuth-telluride thin films are fabricated using three shadow masks. The shadow masks are prepared by standard micro-fabrication processes such as nitridation of Si, dry etching, and wet etching. Thermoelectric power of the as-grown thin film devices with 16 pairs of p-n legs are measured by YAG laser heating at the center of the devices. The thermoelectric power of thermoelectric legs is evaluated to be 180μV/K per one p-n leg pair. According to the Kelvin’s law, it corresponds to 54mV Peltier coefficient per p-n pair.

Measurements of Thermal Conductivity of Thin Films by 3-Omega Method

2008 ◽  
Author(s):  
Saburo Tanaka ◽  
Makoto Takiishi ◽  
Koji Miyazaki ◽  
Hiroshi Tsukamoto
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Thermal Conductivity ◽  
Bismuth Telluride ◽  
Voltage Drop ◽  
Measured Temperature ◽  
Metal Line ◽  
Small Component ◽  
3Ω Method ◽  
Temperature Oscillations

In this study, the thermal conductivity of a bismuth-telluride (Bi2Te3) thin film is measured at room temperature by using the 3ω method [1, 2]. The 3ω method for thin films uses a single metal-line as both the heater and thermometer. An alternating-current driving current at angular frequency ω heats the surface of the sample at a frequency of 2ω. Since the resistance of a metal increases with temperature, temperature oscillations produce an oscillation of the electrical resistance at a frequency of 2ω. Consequently, the voltage drop across the metal line has a small component at 3ω that can be used to measure the temperature oscillations and the thermal response of the sample with a Bismuth-telluride thin film. Differential amplifiers are used to subtract the ω component of the voltage for the measurement of the small 3ω signal as shown in Fig.1. The amplified 3ω component and the attenuated reference voltage are acquired to a personal computer through a 16bit DAC card. The bismuth-telluride thin films are manufactured by flash evaporation and coating. The narrow Aluminum lines for the 3ω method are made by vacuum deposition through metal masks. The measured temperature oscillation ΔT versus ln(ω) yields the thermal conductivity of the substrates. The thermal conductivity of the glass is measured as 0.97 W/(m·K), and that of alumina is 15.4 W/(m·K). These results agree well with the reference data. The thermal conductivities of Bismuth-telluride thin films are calculated from the measured thermal resistances of the films. The measured value for a flash evaporated Bismuth-telluride is 1.20 W/(m·K), and the coated film is 0.51 W/(m·K).

scholarly journals Экспериментальное исследование коэффициента теплопроводности в тонких пленках на основе одностенных углеродных нанотрубок

2020 ◽  
Vol 62 (6) ◽  
pp. 960
Author(s):  
И.А. Тамбасов ◽  
А.С. Воронин ◽  
Н.П. Евсевская ◽  
Ю.М. Кузнецов ◽  
А.В. Лукьяненко ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Thermal Conductivity Coefficient ◽  
Single Walled Carbon Nanotubes ◽  
3Ω Method ◽  
Vacuum Filtration ◽  
Single Walled Carbon ◽  
Walled Carbon Nanotubes

Thin films based on single walled carbon nanotubes with a thickness of 11 ± 3 to 157 ± 18 nm were formed using vacuum filtration. The thermal conductivity coefficient in thin films was studied depending on the thickness and temperature up to 450 K using the 3ω method. It was found that, in the region of 49 nm, the supplied heat from the gold strip began to efficiently propagate into the plane of the thin film. The thermal conductivity coefficient for thin films with a thickness of 49 ± 8 nm was measured according to the 3ω method for bulk samples. It was found that the thermal conductivity in thin films based on single walled carbon nanotubes strongly depends on the thickness and temperature. The thermal conductivity increased sharply (~ 60 times) with increasing thickness from 11 ± 3 to 65 ± 4 nm. In addition, it was revealed that the thermal conductivity coefficient for 157 ± 18 nm thin film rapidly decreased from 211 ± 11 to 27.5 ± 1.4 W · m-1 · K-1 for 300 and 450 K, respectively.

Thermoelectric Power of Bi And Bi1−xSbx Alloy Thin Films And Superlattices Grown by MBE

1997 ◽  
Vol 478 ◽  
Author(s):  
Sunglae Cho ◽  
Antonio DiVenere ◽  
George K. Wong ◽  
John B. Ketterson ◽  
Jerry R. Meyer ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Single Crystal ◽  
Thermoelectric Power ◽  
Bulk Single Crystal ◽  
P Type ◽  
Semiconducting Behavior ◽  
Good Agreement

AbstractWe have measured the thermoelectric power (TEP) of MBE-grown epitaxial Bi and Bi1−xSbx alloy thin films and superlattices as a function of temperature in the range 20–300 K. We have observed that the TEP of a Bi thin film of 1 μm thickness is in good agreement with the bulk single crystal value and that the TEPs for superlattices with 400 Å and 800 Å Bi well thicknesses are enhanced over the bulk values. For x=0.072 and 0.088 in Bi1−xSbx thin films showing semiconducting behavior, TEP enhancement was observed by a factor of two. However as Bi or Bi1−xSbx well thickness decreases in superlattice geometry, the TEP decreases, which may be due to unintentional p-type doping.

Thermodynamics and Microstructure Development in the Thin Film Reaction of Aluminum on Silicon Carbide

1995 ◽  
Vol 403 ◽  
Author(s):  
T. S. Hayes ◽  
F. T. Ray ◽  
K. P. Trumble ◽  
E. P. Kvam
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Silicon Carbide ◽  
Ohmic Contacts ◽  
Microstructure Development ◽  
P Type ◽  
Microstructural Studies

AbstractA refined thernodynamic analysis of the reaction between molen Al and SiC is presented. The calculations indicate much higher Si concentrations for saturation with respect to AkC 3 formation than previously reported. Preliminary microstructural studies confirm the formation of interfacial A14C3 for pure Al thin films on SiC reacted at 9000C. The implications of the calculations and experimental observations for the production of ohmic contacts to p-type SiC are discussed.

Determination of Thermal Conductivity of Amorphous Silicon Thin Films via Non-Contacting Optical Probing

2006 ◽  
Vol 326-328 ◽  
pp. 689-692
Author(s):  
Seung Jae Moon
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Thermal Conductivity ◽  
Amorphous Silicon ◽  
Optical Transmission ◽  
Film Deposition ◽  
Transmission Measurement ◽  
Conductive Heat ◽  
Optical Transmission Measurement

The thermal conductivity of amorphous silicon (a-Si) thin films is determined by using the non-intrusive, in-situ optical transmission measurement. The thermal conductivity of a-Si is a key parameter in understanding the mechanism of the recrystallization of polysilicon (p-Si) during the laser annealing process to fabricate the thin film transistors with uniform characteristics which are used as switches in the active matrix liquid crystal displays. Since it is well known that the physical properties are dependent on the process parameters of the thin film deposition process, the thermal conductivity should be measured. The temperature dependence of the film complex refractive index is determined by spectroscopic ellipsometry. A nanosecond KrF excimer laser at the wavelength of 248 nm is used to raise the temperature of the thin films without melting of the thin film. In-situ transmission signal is obtained during the heating process. The acquired transmission signal is fitted with predictions obtained by coupling conductive heat transfer with multi-layer thin film optics in the optical transmission measurement.

Improvement of Thermal Conductivity of Electroplated Copper Thin-Film Interconnections by Controlling Their Micro Texture

2014 ◽  
Author(s):  
Pornvitoo Rittinon ◽  
Ken Suzuki ◽  
Hideo Miura
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Thermal Conductivity ◽  
Grain Boundaries ◽  
Diffraction Method ◽  
Electron Back Scatter Diffraction ◽  
High Resistivity ◽  
Copper Thin Film ◽  
Electroplated Copper ◽  
The Relationship

Copper thin films are indispensable for the interconnections in the advanced electronic products, such as TSV (Trough Silicon Via), fine bumps, and thin-film interconnections in various devices and interposers. However, it has been reported that both electrical and mechanical properties of the films vary drastically comparing with those of conventional bulk copper. The main reason for the variation can be attributed to the fluctuation of the crystallinity of grain boundaries in the films. Porous or sparse grain boundaries show very high resistivity and brittle fracture characteristic in the films. Thus, the thermal conductivity of the electroplated copper thin films should be varied drastically depending on their micro texture based on the Wiedemann-Franz’s law. Since the copper interconnections are used not only for the electrical conduction but also for the thermal conduction, it is very important to quantitatively evaluate the crystallinity of the polycrystalline thin-film materials and clarify the relationship between the crystallinity and thermal properties of the films. The crystallinity of the interconnections were quantitatively evaluated using an electron back-scatter diffraction method. It was found that the porous grain boundaries which contain a significant amount of vacancies increase the local electrical resistance in the interconnections, and thus, cause the local high Joule heating. Such porous grain boundaries can be eliminated by control the crystallinity of the seed layer material on which the electroplated copper thin film is electroplated.

Long-term Room Temperature Instability in Thermal Conductivity of InGaZnO Thin Films

MRS Advances ◽  
2016 ◽  
Vol 1 (22) ◽  
pp. 1631-1636 ◽  
Author(s):  
Boya Cui ◽  
D. Bruce Buchholz ◽  
Li Zeng ◽  
Michael Bedzyk ◽  
Robert P. H. Chang ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Room Temperature ◽  
Storage Time ◽  
Laser Deposition ◽  
Low Oxygen ◽  
X Ray Diffraction ◽  
3Ω Method ◽  
X Ray

ABSTRACTThe cross-plane thermal conductivities of InGaZnO (IGZO) thin films in different morphologies were measured on three occasions within 19 months, using the 3ω method at room temperature 300 K. Amorphous (a-), semi-crystalline (semi-c-) and crystalline (c-) IGZO films were grown by pulsed laser deposition (PLD), followed by X-ray diffraction (XRD) for evaluation of film quality and crystallinity. Semi-c-IGZO shows the highest thermal conductivity, even higher than the most ordered crystal-like phase. After being stored in dry low-oxygen environment for months, a drastic decrease of semi-c-IGZO thermal conductivity was observed, while the thermal conductivity slightly reduced in c-IGZO and remained unchanged in a-IGZO. This change in thermal conductivity with storage time can be attributed to film structural relaxation and vacancy diffusion to grain boundaries.

scholarly journals Термоэлектрические свойства нанокомпозитного Bi-=SUB=-0.45-=/SUB=-Sb-=SUB=-1.55-=/SUB=-Te-=SUB=-2.985-=/SUB=- с микрочастицами SiO-=SUB=-2-=/SUB=-

2019 ◽  
Vol 53 (6) ◽  
pp. 751
Author(s):  
А.А. Шабалдин ◽  
П.П. Константинов ◽  
Д.А. Курдюков ◽  
Л.Н. Лукьянова ◽  
А.Ю. Самунин ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Solid Solution ◽  
Electrical Conductivity ◽  
Wide Temperature Range ◽  
Figure Of Merit ◽  
Nanostructured Material ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Efficiency ◽  
Thermoelectric Figure ◽  
P Type

AbstractNanocomposite thermoelectrics based on Bi_0.45Sb_1.55Te_2.985 solid solution of p -type conductivity are fabricated by the hot pressing of nanopowders of this solid solution with the addition of SiO_2 microparticles. Investigations of the thermoelectric properties show that the thermoelectric power of the nanocomposites increases in a wide temperature range of 80–420 K, while the thermal conductivity considerably decreases at 80–320 K, which, despite a decrease in the electrical conductivity, leads to an increase in the thermoelectric efficiency in the nanostructured material without the SiO_2 addition by almost 50% (at 300 K). When adding SiO_2, the efficiency decreases. The initial thermoelectric fabricated without nanostructuring, in which the maximal thermoelectric figure of merit ZT = 1 at 390 K, is most efficient at temperatures above 350 K.

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