Effects of MeV Si Ions Modification on the Thermoelectric Properties of SiO2/SiO2+Cu Multilayer Thin Films

2010 ◽  
Vol 1267 ◽  
Author(s):  
John Chacha ◽  
S. Budak ◽  
Cydale Smith ◽  
Marcus Pugh ◽  
Kudus Ogbara ◽  
...  

AbstractThe performance of the thermoelectric materials and devices is shown by a dimensionless figure of merit, ZT = S2σT/K, where S is the Seebeck coefficient, σ is the electrical conductivity, T is the absolute temperature and K is the thermal conductivity. ZT can be increased by increasing S, increasing σ, or decreasing K. We have prepared 100 alternating multi-nano layer of SiO2/SiO2+Cu superlattice films using the ion beam assisted deposition (IBAD). The 5 MeV Si ions bombardments have been performed at the different fluences using the AAMU Pelletron ion beam accelerator to make quantum clusters in the multi-layer superlattice thin films to decrease the cross plane thermal conductivity increase the cross plane Seebeck coefficient and cross plane electrical conductivity. To characterize the thermoelectric thin films before and after Si ion bombardments we have measured the cross-plane Seebeck coefficient, the cross-plane electrical conductivity, and the cross-plane thermal conductivity for different fluences.

2010 ◽  
Vol 1267 ◽  
Author(s):  
S. Budak ◽  
Cydale Smith ◽  
John Chacha ◽  
Marcus Pugh ◽  
Kudus Ogbara ◽  
...  

AbstractThe performance of the thermoelectric devices and materials is shown by a dimensionless figure of merit, ZT = S2σT/K, where S is the Seebeck coefficient, σ is the electrical conductivity, T is the absolute temperature and K is the thermal conductivity. ZT can be increased by increasing S, increasing σ or decreasing K. We have prepared 100 alternating nanolayered films of SiO2/SiO2+CoSb3 using the ion beam assisted deposition (IBAD). The 5 MeV Si ions bombardments have been performed using the AAMU Pelletron ion beam accelerator to make quantum clusters in the nanolayered superlattice films at the three different fluences to decrease the cross plane thermal conductivity, increase the cross plane Seebeck coefficient and cross plane electrical conductivity. We have characterized 100 alternating nanolayered films of SiO2/SiO2+CoSb3 before and after Si ion bombardments as we measured the cross-plane Seebeck coefficient, the cross-plane electrical conductivity, and the cross-plane thermal conductivity for three different fluences.


2010 ◽  
Vol 1267 ◽  
Author(s):  
Marcus Pugh ◽  
S. Budak ◽  
Cydale Smith ◽  
John Chacha ◽  
Kudus Ogbara ◽  
...  

AbstractEffective thermoelectric materials have a low thermal conductivity and a high electrical conductivity. The performance of the thermoelectric materials and devices is shown by a dimensionless figure of merit, ZT = S2σT/K, where S is the Seebeck coefficient, σ is the electrical conductivity, T is the absolute temperature and K is the thermal conductivity. ZT can be increased by increasing S, increasing σ or decreasing K. MeV ion bombardment caused defects and disorder in the film and the grain boundaries of these nano-scale clusters increase phonon scattering and increase the chance of an inelastic interaction and phonon annihilation. We have prepared 100 alternating layers of Si/Si+Ge nanolayered superlattice films using the ion beam assisted deposition (IBAD). The 5 MeV Si ions bombardments have been performed using the AAMU Pelletron ion beam accelerator to make quantum clusters in the nanolayered superlattice films to decrease the cross plane thermal conductivity, increase the cross plane Seebeck coefficient and cross plane electrical conductivity. We have characterized the thermoelectric thin films before and after Si ion bombardments as we measured the cross-plane Seebeck coefficient, the cross-plane electrical conductivity, and the cross-plane thermal conductivity for different fluences


2009 ◽  
Vol 1181 ◽  
Author(s):  
Cydale Smith ◽  
Marcus Pugh ◽  
Hervie Martin ◽  
Rufus Durel Hill ◽  
Brittany James ◽  
...  

AbstractEffective thermoelectric materials have a low thermal conductivity and a high electrical conductivity. The performance of the thermoelectric materials and devices is shown by a dimensionless figure of merit, ZT = S2sσ/ KTC, σ is the electrical conductivity T/KTC, where S is the Seebeck coefficient, T is the absolute temperature and KTC is the thermal conductivity. In this study we have prepared the thermoelectric generator device of Si/Si+Ge multi-layer superlattice films using the ion beam assisted deposition (IBAD). To determine the stoichiometry of the elements of Si and Ge in the grown multilayer films and the thickness of the grown multi-layer films Rutherford Backscattering Spectrometry (RBS) and RUMP simulation software package were used. The 5 MeV Si ion bombardments were performed to make quantum clusters in the multi-layer superlattice thin films to decrease the cross plane thermal conductivity, increase the cross plane Seebeck coefficient and cross plane electrical conductivity.Keywords: Ion bombardment, thermoelectric properties, multi-nanolayers, Figure of merit.


2007 ◽  
Vol 1020 ◽  
Author(s):  
S. Budak ◽  
S. Guner ◽  
C. Muntele ◽  
C. C. Smith ◽  
B. Zheng ◽  
...  

AbstractSemiconducting â-Zn4Sb3and ZrNiSn-based half-heusler compound thin films were prepared by co-evaporation for the application of thermoelectric (TE) materials. High-purity solid zinc and antimony were evaporated by electron beam to grow the â-Zn4Sb3thin film while high-purity zirconium powder and nickel tin powders were evaporated by electron beam to grow the ZrNiSn-based half-heusler compound thin film. Rutherford backscattering spectrometry (RBS) was used to analyze the composition of the thin films. The grown thin films were subjected to 5 MeV Si ions bombardments for generation of nanostructures in the films. We measured the thermal conductivity, Seebeck coefficient, and electrical conductivity of these two systems before and after 5 MeV Si ions beam bombardments. The two material systems have been identified as promising TE materials for the application of thermal-to-electrical energy conversion, but the efficiency still limits their applications. The electronic energy deposited due to ionization in the track of MeV ion beam can cause localized crystallization. The nanostructures produced by MeV ion beam can cause significant change in both the electrical and the thermal conductivity of thin films, thereby improving the efficiency. We used the 3ù-method measurement system to measure the cross-plane thermal conductivity ,the Van der Pauw measurement system to measure the cross-plane electrical conductivity, and the Seebeck-coefficient measurement system to measure the cross-plane Seebeck coefficient. The thermoelectric figures of merit of the two material systems were then derived by calculations using the measurement results. The MeV ion-beam bombardment was found to decrease the thermal conductivity of thin films and increase the efficiency of thermal-to-electrical energy conversion.


2006 ◽  
Vol 929 ◽  
Author(s):  
Bangke Zheng ◽  
S. Budak ◽  
C. Muntele ◽  
Z. Xiao ◽  
S. Celaschi ◽  
...  

ABSTRACTWe made p-type nanoscale super lattice thermoelectric cooling devices which consist of multiple periodic layers of Si1−x Gex / Si, The thickness of each layer ranges between 10 and 50 nm. The super lattice was bombarded by 5 MeV Si ion with different fluencies aiming to form nano-cluster quantum dot structures. We estimated the thermo-electric efficiency of the so fabricated devices, measuring the thin film cross plane thermal conductivity by the 3rd harmonic method, measuring the cross plane Seebeck coefficient, and finally measuring the cross plane electric conductivity before and after ion bombardment. As predicted, the thermo-electric Figure of Merit of the films increases with increasing Si ion fluencies. In addition to the effect of quantum well confinement of the phonon transmission, the nano-scale crystal quantum dots produced by the incident Si beam further adversely affects the thermal conductivity by absorbing and dissipating phonon along the lattice, and therefore further reduces the cross plane thermal conductivity, This process increases the electron density of state therefore increasing Seebeck coefficient, and the electric conductivity.


2008 ◽  
Vol 1100 ◽  
Author(s):  
Sadik Guner ◽  
Satilmis Budak ◽  
Claudiu I Muntele ◽  
Daryush Ila

AbstractMonolayer thin films of YbBiPt and YBiPt have been produced with 560 nm and 394 nm thick respectively in house and their thermoelectric properties were measured before and after MeV ion bombardment. The energy of the ions were selected such that the bombarding Si ions stop in the silicon substrate and deposit only electronic energy by ionization in the deposited thin film. The bombardment by 5.0 MeV Si ions at various fluences changed the homogeneity as well as reducing the internal stress in the films thus affecting the thermal, electrical and Seebeck coefficient of thin films. The stoichiometry of the thin films was determined using Rutherford Backscattering Spectrometry, the thickness has been measured using interferometry and the electrical conductivity was measured using Van der Pauw method. Thermal conductivity of the thin films was measured using an in-house built 3ω thermal conductivity measurement system. Using the measured Seebeck coefficient, thermal conductivity and electrical conductivity we calculated the figure of merit (ZT). We will report our findings of change in the measured figure of merit as a function of bombardment fluence.


2001 ◽  
Vol 691 ◽  
Author(s):  
Bao Yang ◽  
Jian L. Liu ◽  
Kang L. Wang ◽  
Gang Chen

ABSTRACTIn this paper, a set of methods is developed to measure the Seebeck coefficient, electrical conductivity, and thermal conductivity in the cross-plane direction of thin films. The method employs microfabricated heaters, voltage and temperature sensors, and phase-lock amplifiers to determine the temperature and Seebeck voltage oscillation in the cross-plane direction of the samples, from which the thermal conductivity and Seebeck coefficient of thin films are determined simultaneously. The cross-plane electrical conductivity is also measured by a modified transmission line model. These methods are applied to Si/Ge superlattices grown by molecular beam epitaxy.


2009 ◽  
Vol 1181 ◽  
Author(s):  
Marcus Pugh ◽  
Rufus Durel Hill ◽  
Brittany James ◽  
Hervie Martin ◽  
Cydale Smith ◽  
...  

AbstractThe efficiency of the thermoelectric devices is limited by the properties of n- and p-type semiconductors. Effective thermoelectric materials have a low thermal conductivity and a high electrical conductivity. The performance of the thermoelectric materials and devices is shown by a dimensionless figure of merit, ZT = S2σT/K, where S is the Seebeck coefficient, σ is the electrical conductivity, T is the absolute temperature and K is the thermal conductivity. In this study we prepared the thermoelectric generator device of SiO2/SiO2+Au multi-layer super-lattice films using the ion beam assisted deposition (IBAD). In order to determine the stoichiometry of the elements of SiO2 and Au in the grown multilayer films and the thickness of the grown multi-layer films Rutherford Backscattering Spectrometry (RBS) and RUMP simulation software package was used. The 5 MeV Si ion bombardments was performed to make quantum clusters in the multi-layer super-lattice thin films to decrease the cross plane thermal conductivity, increase the cross plane Seebeck coefficient and cross plane electrical conductivity. To characterize the thermoelectric generator devices before and after Si ion bombardments we measured the cross-plane Seebeck coefficient, the cross-plane electrical conductivity, and the cross-plane thermal conductivity for different fluences.


2008 ◽  
Vol 1102 ◽  
Author(s):  
S. Budak ◽  
S. Guner ◽  
T. Hill ◽  
M. Black ◽  
S. B. Judah ◽  
...  

AbstractThermoelectric materials are being important due to their application in both thermoelectric power generation and microelectronic cooling. The thermoelectric power generations convert the heat change to electricity. The waste of heat could be useful if the thermoelectric power generation is applied. Effective thermoelectric materials have a low thermal conductivity and a high electrical conductivity. A high thermal conductivity causes too much heat leakage through heat conduction. The performance of the thermoelectric materials and devices is shown by a dimensionless figure of merit, ZT = S2σT/K, where S is the Seebeck coefficient, σ is the electrical conductivity, T is the absolute temperature and K is the thermal conductivity. ZT can be increased by increasing S, increasing σ, or decreasing K. In this study, we prepared thermoelectric generator devices of SiGe at the thickness of 112 nm using the ion beam assisted deposition (IBAD) system. Rutherford Backscattering Spectrometry (RBS) analysis was used for the elemental analysis. The 5 MeV Si ion bombardment was performed using the AAMU Pelletron ion beam accelerator to make quantum clusters in the film to decrease the cross plane thermal conductivity, increase the cross plane Seebeck coefficient and electrical conductivity. To characterize the thermoelectric generator devices before and after Si ion bombardment we measured the cross plane Seebeck coefficient, electrical conductivity by Van der Pauw method, and thermal conductivity by 3w method for different fluences.


2008 ◽  
Vol 1102 ◽  
Author(s):  
S. Budak ◽  
S. Guner ◽  
C. Muntele ◽  
D. ILA

AbstractWe have deposited 50 nano-layers of 710 nm of SiO2/SiO2+ZrNiSn with a periodic structure consisting of alternating layers where each layer is about 14 nm thick. The purpose of this research is to generate nanolayers of nanostructures of ZrNiSn with SiO2 as host and as buffer layer using a combination of co-deposition and MeV ion bombardment taking advantage of the energy deposited in the MeV ions track to nucleate nanostructures. The performance of the thermoelectric materials and devices is shown by a dimensionless figure of merit, ZT = S2σT/ĸ, where S is the Seebeck coefficient, σ is the electrical conductivity, T is the absolute temperature and ĸ is the thermal conductivity. ZT can be increased by increasing S, increasing σ, or decreasing ĸ. The electrical and thermal properties of the layered structures were studied before and after bombardment by 5 MeV Si ions at seven different fluences ranging from 1014 to 1015 ions/cm2 in order to form nanostructures in layers of SiO2 containing few percent of ZrNiSn. Rutherford Backscattering Spectrometry (RBS) was used to monitor elemental analysis of the film.


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