Surface modification of Si/Ge multi-layers by MeV Si ion bombardment

Budak, S.; Güner, S.; Smith, C.; Minamisawa, R. A.; Zheng, B.; Muntele, C.; Ila, D.

doi:10.1016/j.surfcoat.2009.02.031

Cited by 6 publications

(3 citation statements)

References 18 publications

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“…Similar results were obtained by Leitão et al, who reported that the Ge quantum wells (QWs) deposited on a diode structure containing a Si/Ge multilayer structure were more resistant to the proton irradiation as compared with the single Ge QWs [ 14 ]. As the promising thermoelectric materials, the thermoelectric characteristic of Si/Ge system may be also affected under the radiation environment [ 11 , 15 ]. Zheng et al irradiated the multiple periodic layers of Si 1 − x Ge x /Si employing 5 MeV Si ions, and they found that the thermo-electric figure of merit increases with increasing Si ions fluencies [ 11 ].…”

Section: Introductionmentioning

confidence: 99%

A Theoretical Simulation of the Radiation Responses of Si, Ge, and Si/Ge Superlattice to Low-Energy Irradiation

et al. 2018

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In this study, the low-energy radiation responses of Si, Ge, and Si/Ge superlattice are investigated by an ab initio molecular dynamics method and the origins of their different radiation behaviors are explored. It is found that the radiation resistance of the Ge atoms that are around the interface of Si/Ge superlattice is comparable to bulk Ge, whereas the Si atoms around the interface are more difficult to be displaced than the bulk Si, showing enhanced radiation tolerance as compared with the bulk Si. The mechanisms for defect generation in the bulk and superlattice structures show somewhat different character, and the associated defects in the superlattice are more complex. Defect formation and migration calculations show that in the superlattice structure, the point defects are more difficult to form and the vacancies are less mobile. The enhanced radiation tolerance of the Si/Ge superlattice will benefit for its applications as electronic and optoelectronic devices under radiation environment.

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Section: Introductionmentioning

confidence: 99%

A Theoretical Simulation of the Radiation Responses of Si, Ge, and Si/Ge Superlattice to Low-Energy Irradiation

et al. 2018

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“…The AAMU research approach has been unique in the field of the thermoelectric materials on multi-nanolayered superlattice thin-film systems using MeV ion bombardments to cause nanodots and/or nano-clusters to decrease the thermal conductivity and increase both the Seebeck coefficient and the electrical conductivity. The achieved performance of the devices is remarkable as demonstrated by ZT from the both the cross and inplane measurements at room temperature (Budak et al, 2009b;2013). Recent measurements yielded an impressive ZT of 4.9 in SiO2/SiO2 + Ge multilayer thin films.…”

Section: Introductionmentioning

confidence: 94%

Thermal Treatment Effects on the Thermoelectric Properties of Ni/Si/Si + Sb/Si/Si + Ge/Ni Multilayer Thin Films

Budak¹,

Yang²

2020

American Journal of Engineering and Applied Sciences

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The multilayer thermoelectric devices including Ni/200 layers of Si/Si + Sb/200 layers of Si/Si + Ge/Ni thin films were fabricated using electron beam and DC/RF magnetron sputtering deposition systems. The thickness measurements have been performed using Filmetrics UV thickness measurement system. The Au contacts at the bottom and top of the fabricated thermoelectric devices were measured as 100 nm for each side. Ni layer at the bottom is 108 nm and Ni layer at the top of the multilayer structures is 168 nm. The thickness of 200 layers of Si/Si + Ge thin film is 173 nm and the thickness of 200 layers of Si/Si + Sb thin film is 199 nm. The fabricated thermoelectric devices have total of 402 layers of thin films with the total thickness of 648 nm thickness excluding two Au contact layers. The prepared thin film devices were annealed at different temperatures for one hour to improve the thermoelectric properties. The current studied system has reached some remarkable values of Seebeck coefficients when the suitable annealing temperatures and the suitable operating temperatures of Seebeck measurement system were applied. The multilayer thin film system has reached the Seebeck coefficient of-344.8 μV/K when the annealed temperature was 100°C and the operating temperature was 320 K. One of the main problems with the thermoelectric devices is having higher temperature dissipation during the operation of the devices. Ni thin film was used in the fabrication process to remove excess of the heat as a heat sink from the thermoelectric devices. This will bring new approach for the high efficient thermoelectric devices. The goal of the manuscript is to improve the thermoelectric properties of the fabricated thin film thermoelectric devices using Ni thin films and the thermal treatment. The resistivity values decreased when the annealing temperatures increased. The highest power factor values were reached when the thermoelectric devices were annealed at 100°C. Mobility values increased when the suitable temperatures were applied for thermal treatment.

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“…ZT values could be tailored by increasing the Seebeck coefficient S and the electrical conductivity σ, and reducing the thermal conductivity K by bombarding the structure with MeV Si ions. [11]. In addition to, the quantum well confinement of phonon transmission due to Bragg reflection at lattice interfaces [7,8] the defects and disorder in the lattice caused by ion bombardment and the grain boundaries of these nanoscale clusters increase phonon scattering and increase the chance of an inelastic interaction and phonon annihilation.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2010

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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 = S 2 σT/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.

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Surface modification of Si/Ge multi-layers by MeV Si ion bombardment

Cited by 6 publications

References 18 publications

A Theoretical Simulation of the Radiation Responses of Si, Ge, and Si/Ge Superlattice to Low-Energy Irradiation

A Theoretical Simulation of the Radiation Responses of Si, Ge, and Si/Ge Superlattice to Low-Energy Irradiation

Thermal Treatment Effects on the Thermoelectric Properties of Ni/Si/Si + Sb/Si/Si + Ge/Ni Multilayer Thin Films

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

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