Effect of MeV Si Ion Bombardment on Thermoelectric Characteristics of Sequentially Deposited SiO2/AuxSiO2(1-x) Nanolayers

2006 ◽  
Vol 929 ◽  
Author(s):  
S. Budak ◽  
B. Zheng ◽  
C. Muntele ◽  
Z. Xiao ◽  
I. Muntele ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Seebeck Coefficient ◽  
Electric Conductivity ◽  
Figure Of Merit ◽  
Rutherford Backscattering Spectrometry ◽  
Cooling System ◽  
Ion Beam ◽  
Cluster Structure ◽  
Thermoelectric Efficiency ◽  
Before And After

ABSTRACTWe made 50 and 100 periodic nano-layers of electro-cooling system consisting of SiO2/AuxSiO2(1−x) super lattice with Au layer deposited on both side as metal contact using Ion Beam Assisted Deposition (IBAD) system. The deposited multi-layer films have a periodic structure consisting of alternating layers where each layer is between 1-10 nm thick. The ultimate objective of this research is to tailor the figure of merit of layered structures used as thermoelectric generators. The super lattices were then bombarded by 5 MeV Si ion at different four fluences to form nano-cluster structure. The film thickness and stoichiometry were monitored by Rutherford Backscattering Spectrometry (RBS) before and after MeV bombardments. We measured the thermoelectric efficiency of the fabricated device before and after MeV bombardments. To accomplish this we measured the cross plane thermal conductivity by 3rd harmonic method, measured cross plane Seebeck coefficient, and measured electric conductivity using Van Der Pauw method before and after 5 MeV Si Bombardments. As predicted the electronic energy deposited due to ionization by MeV Si beam in its track produces nano-scale structures which disrupt and confine phonon transmission therefore reducing thermal conductivity, increasing electron density of state so as to increase Seebeck coefficient, and electric conductivity, thus increasing figure of merit. We will present our findings during the meeting.* Research sponsored by the Center for Irradiation of Materials, Alabama A&M University and by the AAMURI Center for Advanced Propulsion Materials under the contract number NAG8-1933 from NASA, and by National Science Foundation under Grant No. EPS-0447675.

Improvement on Thermoelectric Characteristics of Layered Nanostructure by Ion Beam Bombardment

2006 ◽  
Vol 929 ◽  
Author(s):  
Bangke Zheng ◽  
S. Budak ◽  
C. Muntele ◽  
Z. Xiao ◽  
S. Celaschi ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Seebeck Coefficient ◽  
Electric Conductivity ◽  
Ion Beam ◽  
Thermo Electric ◽  
Super Lattice ◽  
Before And After ◽  
The Cross ◽  
Nano Cluster ◽  
P Type

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.

Thermoelectric Properties of YbBiPt and YBiPt Thin Films

2008 ◽  
Vol 1100 ◽  
Author(s):  
Sadik Guner ◽  
Satilmis Budak ◽  
Claudiu I Muntele ◽  
Daryush Ila
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Rutherford Backscattering Spectrometry ◽  
Conductivity Measurement ◽  
Electronic Energy ◽  
Before And After

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.

Thermoelectric Generators of Sequentially Deposited Si/Si+Ge Nano-layered Superlattices

2009 ◽  
Vol 1181 ◽  
Author(s):  
Cydale Smith ◽  
Marcus Pugh ◽  
Hervie Martin ◽  
Rufus Durel Hill ◽  
Brittany James ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Thermoelectric Materials ◽  
Figure Of Merit ◽  
Rutherford Backscattering Spectrometry ◽  
Ion Beam ◽  
Absolute Temperature ◽  
Simulation Software ◽  
The Cross

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.

MeV Si Ions Bombardment Effects on the Properties of Nano-Layers of SiO2/SiO2+Ag

2008 ◽  
Vol 1074 ◽  
Author(s):  
Sadik Guner ◽  
Satilmis Budak ◽  
Claudiu I Muntele ◽  
Cydale C Smith ◽  
Daryush Ila
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Layered Structure ◽  
Figure Of Merit ◽  
Rutherford Backscattering Spectrometry ◽  
Conductivity Measurement ◽  
Electronic Energy ◽  
Before And After

ABSTRACTWe have grown 100 periodic SiO2/SiO2+Ag multi-nano-layered systems where the SiO2+Ag layers were 7.26 nm and SiO2 buffer layer were 4 nm, total thickness is 563 nm. Using interferometer as well as in-situ thickness monitoring, we measured the thickness of the layers; using Rutherford Backscattering Spectrometry (RBS) measured the concentration and distribution of Ag in SiO2. The electrical conductivity, thermal conductivity and the Seebeck coefficient of the layered structure were measured at room temperature before and after bombardment by 5 MeV Si ions. The energy of the Si ions were chosen such that the ions are stopped in the silicon substrate and only electronic energy due to ionization is deposited in the layered structure. The electrical conductivity 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 figure of merit as a function of the bombardment fluence.

MeV Si Ions Bombardment Effects on SiO2/SiO2-ZrNiSn Nano-layered Thermoelectric Generator

2008 ◽  
Vol 1102 ◽  
Author(s):  
S. Budak ◽  
S. Guner ◽  
C. Muntele ◽  
D. ILA
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Thermal Properties ◽  
Seebeck Coefficient ◽  
Figure Of Merit ◽  
Thermoelectric Generator ◽  
Rutherford Backscattering Spectrometry ◽  
Absolute Temperature ◽  
Dimensionless Figure Of Merit ◽  
Before And After

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.

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 ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Ion Beam ◽  
Absolute Temperature ◽  
Conductivity Increase ◽  
Before And After ◽  
The Cross ◽  
Thermoelectric Thin Films

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.

Fabrication and Characterization of Thermoelectric Generators From SiO2/SiO2+Au Nano-layered Superlattices

2009 ◽  
Vol 1181 ◽  
Author(s):  
Marcus Pugh ◽  
Rufus Durel Hill ◽  
Brittany James ◽  
Hervie Martin ◽  
Cydale Smith ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Thermoelectric Materials ◽  
Thermoelectric Generator ◽  
Rutherford Backscattering Spectrometry ◽  
Ion Beam ◽  
Simulation Software ◽  
Super Lattice ◽  
The Cross

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.

Investigating the Effects of Sodium Chloride Particles on Thermoelectric Properties of Bismuth Telluride

2017 ◽  
Author(s):  
T. Alexander ◽  
M. Rahman ◽  
R. Asmatulu
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Sodium Chloride ◽  
Seebeck Coefficient ◽  
Bismuth Telluride ◽  
Figure Of Merit ◽  
Hot Water ◽  
Dimensionless Figure Of Merit ◽  
Before And After ◽  
Baseline Sample

Cylindrical pellets of near stoichiometric bismuth telluride (Bi2Te3) powder with NaCl particles were made using a cold pressing and pressureless sintering technique. The sodium chloride was leached out from the samples in hot water, resulting in porous samples with varying levels of porosity. The electrical conductivity, Seebeck coefficient, and thermal conductivity were measured at room temperature using a testing apparatus designed and built by the researcher, both before and after the leaching of sodium chloride. From this data, the figure of merit was calculated. Samples of pure bismuth telluride (0% NaCl) served as the baseline samples for comparison. Both the presence of NaCl and pores were efficient at increasing the dimensionless figure of merit. Porous samples initially containing 20% NaCl had a 37.55% higher figure of merit compared to baseline samples, and an 89.07% increase in the figure of merit was seen from the solid samples with NaCl inclusions at a concentration of 30% by volume. The electrical conductivity was negatively affected by both inclusions and porosity, but significant increases in Seebeck coefficient, and reduced thermal conductivity were significantly enough for an overall increase in dimensionless figure of merit. The figure of merit for the baseline sample was approximately 0.18, and the highest values observed for the NaCl inclusion and porous samples were 0.34 and 0.25 respectively. These values are far less than that of what is considered a state of the art thermoelectric material, but the materials and methods used were simple, inexpensive, and scalable, showing great potential for applicability for use with optimized thermoelectric materials in hopes of further increasing their figure of merit.

MeV Si Ions Bombardment Effects on the Thermoelectric Properties of Si/Si+Ge Multi-Layer Superlttice Nanolayered Films

2010 ◽  
Vol 1267 ◽  
Author(s):  
Marcus Pugh ◽  
S. Budak ◽  
Cydale Smith ◽  
John Chacha ◽  
Kudus Ogbara ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Thermoelectric Materials ◽  
Phonon Scattering ◽  
Ion Beam ◽  
Absolute Temperature ◽  
Inelastic Interaction ◽  
Before And After ◽  
The Cross

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

MeV Ion Beam Bombardments Effects on the Thermoelectric Properties of Zn4Sb3 / CeFe(4-x)CoxSb12 Nano-Layered Superlattices

2006 ◽  
Vol 974 ◽  
Author(s):  
S. Budak ◽  
C. C. Smith ◽  
B. Zheng ◽  
C. I. Muntele ◽  
R. L. Zimmerman ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Energy Conversion ◽  
Rutherford Backscattering Spectrometry ◽  
Ion Beam ◽  
Electrical Energy ◽  
3Ω Method ◽  
Ion Beam Assisted Deposition ◽  
Before And After ◽  
Conductivity Of Thin Films

ABSTRACTWe prepared multilayers of semiconducting half-heusler β-Zn4Sb3 and skutterudites CeFe(4-x)CoxSb12 compound thin films by ion beam assisted deposition (IBAD) system for the application of thermoelectric (TE) materials. Rutherford backscattering spectrometry (RBS) was used to analyze the composition of thin films. The thin films were then bombarded by 5 MeV Si ions for generation of nanodots in the films. We measured the cross-plane thermal conductivity by a house developed 3ω-method system, cross-plane Seebeck coefficient by a (MMR) Seebeck system, and cross plane electrical conductivity of these nanolayered systems by a (MMR) Hall system before and after bombardment. Both β-Zn4Sb3 and CeFe(4-x)CoxSb12 systems have been identified as promising thermoelectric materials for the application of thermal-to-electrical energy conversion. The nanodots produced by MeV ion beam can cause significant change in both electrical and thermal conductivity of thin films, thus improving the efficiency. The MeV ion-beam bombardment resulted in decrease in the thermal conductivity of thin films and increase in the efficiency of thermal-to-electrical energy conversion.

Sign in / Sign up

Export Citation Format

Share Document