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Description
This dissertation is on the study of structural and optical properties of some III-V and II-VI compound semiconductors. The first part of this dissertation is a study of the deformation mechanisms associated with nanoindentation and nanoscratching of InP, GaN, and ZnO crystals. The second part is an investigation of some fundamental issues regarding compositional fluctuations and microstructure in GaInNAs and InAlN alloys. In the first part, the microstructure of (001) InP scratched in an atomic force microscope with a small diamond tip has been studied as a function of applied normal force and crystalline direction in order to understand at the nanometer scale the deformation mechanisms in the zinc-blende structure. TEM images show deeper dislocation propagation for scratches along <110> compared to <100>. High strain fields were observed in <100> scratches, indicating hardening due to locking of dislocations gliding on different slip planes. Reverse plastic flow have been observed in <110> scratches in the form of pop-up events that result from recovery of stored elastic strain. In a separate study, nanoindentation-induced plastic deformation has been studied in c-, a-, and m-plane ZnO single crystals and c-plane GaN respectively, to study the deformation mechanism in wurtzite hexagonal structures. TEM results reveal that the prime deformation mechanism is slip on basal planes and in some cases, on pyramidal planes, and strain built up along particular directions. No evidence of phase transformation or cracking was observed in both materials. CL imaging reveals quenching of near band-edge emission by dislocations. In the second part, compositional inhomogeneity in quaternary GaInNAs and ternary InAlN alloys has been studied using TEM. It is shown that exposure to antimony during growth of GaInNAs results in uniform chemical composition in the epilayer, as antimony suppresses the surface mobility of adatoms that otherwise leads to two-dimensional growth and elemental segregation. In a separate study, compositional instability is observed in lattice-matched InAlN films grown on GaN, for growth beyond a certain thickness. Beyond 200 nm of thickness, two sub-layers with different indium content are observed, the top one with lower indium content.
ContributorsHuang, Jingyi (Author) / Ponce, Fernando A. (Thesis advisor) / Carpenter, Ray W (Committee member) / Smith, David J. (Committee member) / Yu, Hongbin (Committee member) / Treacy, Michael Mj (Committee member) / Arizona State University (Publisher)
Created2013
Description
This thesis mainly focuses on the study of quantum efficiency (QE) and its measurement, especially for nanowires (NWs). First, a brief introduction of nano-technology and nanowire is given to describe my initial research interest. Next various fundamental kinds of recombination mechanisms are described; both for radiative and non-radiative processes. This is an introduction for defining the internal quantum efficiency (IQE). A relative IQE measurement method is shown following that. Then it comes to the major part of the thesis discussing a procedure of quantum efficiency measurement using photoluminescence (PL) method and an integrating sphere, which has not been much applied to nanowires (NWs). In fact this is a convenient and useful approach for evaluating the quality of NWs since it considers not only the PL emission but also the absorption of NWs. The process is well illustrated and performed with both wavelength-dependent and power-dependent measurements. The measured PLQE is in the range of 0.3% ~ 5.4%. During the measurement, a phenomenon called photodegradation is observed and examined by a set of power-dependence measurements. This effect can be a factor for underestimating the PLQE and a procedure is introduced during the sample preparation process which managed to reduce this effect for some degree.
ContributorsChen, Dongzi (Author) / Ning, Cun-Zheng (Thesis advisor) / Zhang, Yong-Hang (Committee member) / Yu, Hongbin (Committee member) / Arizona State University (Publisher)
Created2012
Description
The objective of this dissertation is to study the use of metamaterials as narrow-band and broadband selective absorbers for opto-thermal and solar thermal energy conversion. Narrow-band selective absorbers have applications such as plasmonic sensing and cancer treatment, while one of the main applications of selective metamaterials with broadband absorption is efficiently converting solar energy into heat as solar absorbers.
This dissertation first discusses the use of gold nanowires as narrow-band selective metamaterial absorbers. An investigation into plasmonic localized heating indicated that film-coupled gold nanoparticles exhibit tunable selective absorption based on the size of the nanoparticles. By using anodized aluminum oxide templates, aluminum nanodisc narrow-band absorbers were fabricated. A metrology instrument to measure the reflectance and transmittance of micro-scale samples was also developed and used to measure the reflectance of the aluminum nanodisc absorbers (220 µm diameter area). Tuning of the resonance wavelengths of these absorbers can be achieved through changing their geometry. Broadband absorption can be achieved by using a combination of geometries for these metamaterials which would facilitate their use as solar absorbers.
Recently, solar energy harvesting has become a topic of considerable research investigation due to it being an environmentally conscious alternative to fossil fuels. The next section discusses the steady-state temperature measurement of a lab-scale multilayer solar absorber, named metafilm. A lab-scale experimental setup is developed to characterize the solar thermal performance of selective solar absorbers. Under a concentration factor of 20.3 suns, a steady-state temperature of ~500 degrees Celsius was achieved for the metafilm compared to 375 degrees Celsius for a commercial black absorber under the same conditions. Thermal durability testing showed that the metafilm could withstand up to 700 degrees Celsius in vacuum conditions and up to 400 degrees Celsius in atmospheric conditions with little degradation of its optical and radiative properties. Moreover, cost analysis of the metafilm found it to cost significantly less ($2.22 per square meter) than commercial solar coatings ($5.41-100 per square meter).
Finally, this dissertation concludes with recommendations for further studies like using these selective metamaterials and metafilms as absorbers and emitters and using the aluminum nanodiscs on glass as selective filters for photovoltaic cells to enhance solar thermophotovoltaic energy conversion.
This dissertation first discusses the use of gold nanowires as narrow-band selective metamaterial absorbers. An investigation into plasmonic localized heating indicated that film-coupled gold nanoparticles exhibit tunable selective absorption based on the size of the nanoparticles. By using anodized aluminum oxide templates, aluminum nanodisc narrow-band absorbers were fabricated. A metrology instrument to measure the reflectance and transmittance of micro-scale samples was also developed and used to measure the reflectance of the aluminum nanodisc absorbers (220 µm diameter area). Tuning of the resonance wavelengths of these absorbers can be achieved through changing their geometry. Broadband absorption can be achieved by using a combination of geometries for these metamaterials which would facilitate their use as solar absorbers.
Recently, solar energy harvesting has become a topic of considerable research investigation due to it being an environmentally conscious alternative to fossil fuels. The next section discusses the steady-state temperature measurement of a lab-scale multilayer solar absorber, named metafilm. A lab-scale experimental setup is developed to characterize the solar thermal performance of selective solar absorbers. Under a concentration factor of 20.3 suns, a steady-state temperature of ~500 degrees Celsius was achieved for the metafilm compared to 375 degrees Celsius for a commercial black absorber under the same conditions. Thermal durability testing showed that the metafilm could withstand up to 700 degrees Celsius in vacuum conditions and up to 400 degrees Celsius in atmospheric conditions with little degradation of its optical and radiative properties. Moreover, cost analysis of the metafilm found it to cost significantly less ($2.22 per square meter) than commercial solar coatings ($5.41-100 per square meter).
Finally, this dissertation concludes with recommendations for further studies like using these selective metamaterials and metafilms as absorbers and emitters and using the aluminum nanodiscs on glass as selective filters for photovoltaic cells to enhance solar thermophotovoltaic energy conversion.
ContributorsAlshehri, Hassan (Author) / Wang, Liping (Thesis advisor) / Phelan, Patrick (Committee member) / Rykaczewski, Konrad (Committee member) / Wang, Robert (Committee member) / Yu, Hongbin (Committee member) / Arizona State University (Publisher)
Created2018
Description
To date, the most popular and dominant material for commercial solar cells is
crystalline silicon (or wafer-Si). It has the highest cell efficiency and cell lifetime out
of all commercial solar cells. Although the potential of crystalline-Si solar cells in
supplying energy demands is enormous, their future growth will likely be constrained
by two major bottlenecks. The first is the high electricity input to produce
crystalline-Si solar cells and modules, and the second is the limited supply of silver
(Ag) reserves. These bottlenecks prevent crystalline-Si solar cells from reaching
terawatt-scale deployment, which means the electricity produced by crystalline-Si
solar cells would never fulfill a noticeable portion of our energy demands in the future.
In order to solve the issue of Ag limitation for the front metal grid, aluminum (Al)
electroplating has been developed as an alternative metallization technique in the
fabrication of crystalline-Si solar cells. The plating is carried out in a
near-room-temperature ionic liquid by means of galvanostatic electrolysis. It has been
found that dense, adherent Al deposits with resistivity in the high 10^–6 ohm-cm range
can be reproducibly obtained directly on Si substrates and nickel seed layers. An
all-Al Si solar cell, with an electroplated Al front electrode and a screen-printed Al
back electrode, has been successfully demonstrated based on commercial p-type
monocrystalline-Si solar cells, and its efficiency is approaching 15%. Further
optimization of the cell fabrication process, in particular a suitable patterning
technique for the front silicon nitride layer, is expected to increase the efficiency of
the cell to ~18%. This shows the potential of Al electroplating in cell metallization is
promising and replacing Ag with Al as the front finger electrode is feasible.
crystalline silicon (or wafer-Si). It has the highest cell efficiency and cell lifetime out
of all commercial solar cells. Although the potential of crystalline-Si solar cells in
supplying energy demands is enormous, their future growth will likely be constrained
by two major bottlenecks. The first is the high electricity input to produce
crystalline-Si solar cells and modules, and the second is the limited supply of silver
(Ag) reserves. These bottlenecks prevent crystalline-Si solar cells from reaching
terawatt-scale deployment, which means the electricity produced by crystalline-Si
solar cells would never fulfill a noticeable portion of our energy demands in the future.
In order to solve the issue of Ag limitation for the front metal grid, aluminum (Al)
electroplating has been developed as an alternative metallization technique in the
fabrication of crystalline-Si solar cells. The plating is carried out in a
near-room-temperature ionic liquid by means of galvanostatic electrolysis. It has been
found that dense, adherent Al deposits with resistivity in the high 10^–6 ohm-cm range
can be reproducibly obtained directly on Si substrates and nickel seed layers. An
all-Al Si solar cell, with an electroplated Al front electrode and a screen-printed Al
back electrode, has been successfully demonstrated based on commercial p-type
monocrystalline-Si solar cells, and its efficiency is approaching 15%. Further
optimization of the cell fabrication process, in particular a suitable patterning
technique for the front silicon nitride layer, is expected to increase the efficiency of
the cell to ~18%. This shows the potential of Al electroplating in cell metallization is
promising and replacing Ag with Al as the front finger electrode is feasible.
ContributorsSun, Wen-Cheng (Author) / Tao, Meng (Thesis advisor) / Vasileska, Dragica (Committee member) / Yu, Hongbin (Committee member) / Goryll, Michael (Committee member) / Arizona State University (Publisher)
Created2016
Description
Group III-nitride semiconductors have been commercially used in the fabrication of light-emitting diodes and laser diodes, covering the ultraviolet-visible-infrared spectral range and exhibit unique properties suitable for modern optoelectronic applications. InGaN ternary alloys have energy band gaps ranging from 0.7 to 3.4 eV. It has a great potential in the application for high efficient solar cells. AlGaN ternary alloys have energy band gaps ranging from 3.4 to 6.2 eV. These alloys have a great potential in the application of deep ultra violet laser diodes. However, there are still many issues with these materials that remain to be solved. In this dissertation, several issues concerning structural, electronic, and optical properties of III-nitrides have been investigated using transmission electron microscopy. First, the microstructure of InxGa1-xN (x = 0.22, 0.46, 0.60, and 0.67) films grown by metal-modulated epitaxy on GaN buffer /sapphire substrates is studied. The effect of indium composition on the structure of InGaN films and strain relaxation is carefully analyzed. High luminescence intensity, low defect density, and uniform full misfit strain relaxation are observed for x = 0.67. Second, the properties of high-indium-content InGaN thin films using a new molecular beam epitaxy method have been studied for applications in solar cell technologies. This method uses a high quality AlN buffer with large lattice mismatch that results in a critical thickness below one lattice parameter. Finally, the effect of different substrates and number of gallium sources on the microstructure of AlGaN-based deep ultraviolet laser has been studied. It is found that defects in epitaxial layer are greatly reduced when the structure is deposited on a single crystal AlN substrate. Two gallium sources in the growth of multiple quantum wells active region are found to cause a significant improvement in the quality of quantum well structures.
ContributorsWei, Yong (Author) / Ponce, Fernando (Thesis advisor) / Chizmeshya, Andrew (Committee member) / McCartney, Martha (Committee member) / Menéndez, Jose (Committee member) / Yu, Hongbin (Committee member) / Arizona State University (Publisher)
Created2014
Description
Li-ion batteries are being used on a large scale varying from consumer electronics to electric vehicles. The key to efficient use of batteries is implementing a well-developed battery management system. Also, there is an opportunity for research for improving the battery performance in terms of size and capacity. For all this it is imperative to develop Li-ion cell model that replicate the performance of a physical cell unit. This report discusses a dual polarization cell model and a battery management system implemented to control the operation of the battery. The Li-ion cell is modelled, and the performance is observed in PLECS environment.
The main aspect of this report studies the viability of Li-ion battery application in Battery Energy Storage System (BESS) in Modular multilevel converter (MMC). MMC-based BESS is a promising solution for grid-level battery energy storage to accelerate utilization and integration of intermittent renewable energy resources, i.e., solar and wind energy. When the battery units are directly integrated in submodules (SMs) without dc-dc interfaced converters, this configuration provides highest system efficiency and lowest cost. However, the lifetime of battery will be affected by the low-frequency components contained in arm currents, which has not been thoroughly investigated. This paper investigates impact of various low-frequency arm-current ripples on lifetime of Li-ion battery cells and evaluate performance of battery charging and discharging in an MMC-BESS without dc-dc interfaced converters.
The main aspect of this report studies the viability of Li-ion battery application in Battery Energy Storage System (BESS) in Modular multilevel converter (MMC). MMC-based BESS is a promising solution for grid-level battery energy storage to accelerate utilization and integration of intermittent renewable energy resources, i.e., solar and wind energy. When the battery units are directly integrated in submodules (SMs) without dc-dc interfaced converters, this configuration provides highest system efficiency and lowest cost. However, the lifetime of battery will be affected by the low-frequency components contained in arm currents, which has not been thoroughly investigated. This paper investigates impact of various low-frequency arm-current ripples on lifetime of Li-ion battery cells and evaluate performance of battery charging and discharging in an MMC-BESS without dc-dc interfaced converters.
ContributorsPuranik, Ishaan (Author) / Qin, Jiangchao (Thesis advisor) / Karady, George G. (Committee member) / Yu, Hongbin (Committee member) / Arizona State University (Publisher)
Created2018
Description
ABSTRACT
Autonomous smart windows may be integrated with a stack of active components, such as electrochromic devices, to modulate the opacity/transparency by an applied voltage. Here, we describe the processing and performance of two classes of visibly-transparent photovoltaic materials, namely inorganic (ZnO thin film) and fully organic (PCDTBT:PC70BM), for integration with electrochromic stacks.
Sputtered ZnO (2% Mn) films on ITO, with transparency in the visible range, were used to fabricate metal-semiconductor (MS), metal-insulator-semiconductor (MIS), and p-i-n heterojunction devices, and their photovoltaic conversion under ultraviolet (UV) illumination was evaluated with and without oxygen plasma-treated surface electrodes (Au, Ag, Al, and Ti/Ag). The MS Schottky parameters were fitted against the generalized Bardeen model to obtain the density of interface states (Dit ≈ 8.0×1011 eV−1cm−2) and neutral level (Eo ≈ -5.2 eV). These devices exhibited photoconductive behavior at λ = 365 nm, and low-noise Ag-ZnO detectors exhibited responsivity (R) and photoconductive gain (G) of 1.93×10−4 A/W and 6.57×10−4, respectively. Confirmed via matched-pair analysis, post-metallization, oxygen plasma treatment of Ag and Ti/Ag electrodes resulted in increased Schottky barrier heights, which maximized with a 2 nm SiO2 electron blocking layer (EBL), coupled with the suppression of recombination at the metal/semiconductor interface and blocking of majority carriers. For interdigitated devices under monochromatic UV-C illumination, the open-circuit voltage (Voc) was 1.2 V and short circuit current density (Jsc), due to minority carrier tunneling, was 0.68 mA/cm2.
A fully organic bulk heterojunction photovoltaic device, composed of poly[N-9’-heptadecanyl-2,7-carbazole-alt-5,5-(4’,7’-di-2-thienyli2’,1’,3’-benzothiadiazole)]:phenyl-C71-butyric-acidmethyl (PCDTBT:PC70BM), with corresponding electron and hole transport layers, i.e., LiF with Al contact and conducting
on-conducting (nc) PEDOT:PSS (with ITO/PET or Ag nanowire/PDMS contacts; the illuminating side), respectively, was developed. The PCDTBT/PC70BM/PEDOT:PSS(nc)/ITO/PET stack exhibited the highest performance: power conversion efficiency (PCE) ≈ 3%, Voc = 0.9V, and Jsc ≈ 10-15 mA/cm2. These stacks exhibited high visible range transparency, and provided the requisite power for a switchable electrochromic stack having an inkjet-printed, optically-active layer of tungsten trioxide (WO3), peroxo-tungstic acid dihydrate, and titania (TiO2) nano-particle-based blend. The electrochromic stacks (i.e., PET/ITO/LiClO4/WO3 on ITO/PET and Ag nanowire/PDMS substrates) exhibited optical switching under external bias from the PV stack (or an electrical outlet), with 7 s coloration time, 8 s bleaching time, and 0.36-0.75 optical modulation at λ = 525 nm. The devices were paired using an Internet of Things controller that enabled wireless switching.
Autonomous smart windows may be integrated with a stack of active components, such as electrochromic devices, to modulate the opacity/transparency by an applied voltage. Here, we describe the processing and performance of two classes of visibly-transparent photovoltaic materials, namely inorganic (ZnO thin film) and fully organic (PCDTBT:PC70BM), for integration with electrochromic stacks.
Sputtered ZnO (2% Mn) films on ITO, with transparency in the visible range, were used to fabricate metal-semiconductor (MS), metal-insulator-semiconductor (MIS), and p-i-n heterojunction devices, and their photovoltaic conversion under ultraviolet (UV) illumination was evaluated with and without oxygen plasma-treated surface electrodes (Au, Ag, Al, and Ti/Ag). The MS Schottky parameters were fitted against the generalized Bardeen model to obtain the density of interface states (Dit ≈ 8.0×1011 eV−1cm−2) and neutral level (Eo ≈ -5.2 eV). These devices exhibited photoconductive behavior at λ = 365 nm, and low-noise Ag-ZnO detectors exhibited responsivity (R) and photoconductive gain (G) of 1.93×10−4 A/W and 6.57×10−4, respectively. Confirmed via matched-pair analysis, post-metallization, oxygen plasma treatment of Ag and Ti/Ag electrodes resulted in increased Schottky barrier heights, which maximized with a 2 nm SiO2 electron blocking layer (EBL), coupled with the suppression of recombination at the metal/semiconductor interface and blocking of majority carriers. For interdigitated devices under monochromatic UV-C illumination, the open-circuit voltage (Voc) was 1.2 V and short circuit current density (Jsc), due to minority carrier tunneling, was 0.68 mA/cm2.
A fully organic bulk heterojunction photovoltaic device, composed of poly[N-9’-heptadecanyl-2,7-carbazole-alt-5,5-(4’,7’-di-2-thienyli2’,1’,3’-benzothiadiazole)]:phenyl-C71-butyric-acidmethyl (PCDTBT:PC70BM), with corresponding electron and hole transport layers, i.e., LiF with Al contact and conducting
on-conducting (nc) PEDOT:PSS (with ITO/PET or Ag nanowire/PDMS contacts; the illuminating side), respectively, was developed. The PCDTBT/PC70BM/PEDOT:PSS(nc)/ITO/PET stack exhibited the highest performance: power conversion efficiency (PCE) ≈ 3%, Voc = 0.9V, and Jsc ≈ 10-15 mA/cm2. These stacks exhibited high visible range transparency, and provided the requisite power for a switchable electrochromic stack having an inkjet-printed, optically-active layer of tungsten trioxide (WO3), peroxo-tungstic acid dihydrate, and titania (TiO2) nano-particle-based blend. The electrochromic stacks (i.e., PET/ITO/LiClO4/WO3 on ITO/PET and Ag nanowire/PDMS substrates) exhibited optical switching under external bias from the PV stack (or an electrical outlet), with 7 s coloration time, 8 s bleaching time, and 0.36-0.75 optical modulation at λ = 525 nm. The devices were paired using an Internet of Things controller that enabled wireless switching.
ContributorsAzhar, Ebraheem (Author) / Yu, Hongbin (Thesis advisor) / Dey, Sandwip (Thesis advisor) / Goryll, Michael (Committee member) / Alford, Terry (Committee member) / Arizona State University (Publisher)
Created2018
Description
The larger tolerance to lattice mismatch in growth of semiconductor nanowires (NWs) offers much more flexibility for achieving a wide range of compositions and bandgaps via alloying within a single substrate. The bandgap of III-V InGaAsP alloy NWs can be tuned to cover a wide range of (0.4, 2.25) eV, appealing for various optoelectronic applications such as photodetectors, solar cells, Light Emitting Diodes (LEDs), lasers, etc., given the existing rich knowledge in device fabrication based on these materials.
This dissertation explores the growth of InGaAsP alloys using a low-cost method that could be potentially important especially for III-V NW-based solar cells. The NWs were grown by Vapor-Liquid-Solid (VLS) and Vapor-Solid (VS) mechanisms using a Low-Pressure Chemical Vapor Deposition (LPCVD) technique. The concept of supersaturation was employed to control the morphology of NWs through the interplay between VLS and VS growth mechanisms. Comprehensive optical and material characterizations were carried out to evaluate the quality of the grown materials.
The growth of exceptionally high quality III-V phosphide NWs of InP and GaP was studied with an emphasis on the effects of vastly different sublimation rates of the associated III and V elements. The incorporation of defects exerted by deviation from stoichiometry was examined for GaP NWs, with an aim towards maximization of bandedge-to-defect emission ratio. In addition, a VLS-VS assisted growth of highly stoichiometric InP thin films and nano-networks with a wide temperature window from 560◦C to 720◦C was demonstrated. Such growth is shown to be insensitive to the type of substrates such as silicon, InP, and fused quartz. The dual gradient method was exploited to grow composition-graded ternary alloy NWs of InGaP, InGaAs, and GaAsP with different bandgaps ranging from 0.6 eV to 2.2 eV, to be used for making laterally-arrayed multiple bandgap (LAMB) solar cells. Furthermore, a template-based growth of the NWs was attempted based on the Si/SiO2 substrate. Such platform can be used to grow a wide range of alloy nanopillar materials, without being limited by typical lattice mismatch, providing a low cost universal platform for future PV solar cells.
This dissertation explores the growth of InGaAsP alloys using a low-cost method that could be potentially important especially for III-V NW-based solar cells. The NWs were grown by Vapor-Liquid-Solid (VLS) and Vapor-Solid (VS) mechanisms using a Low-Pressure Chemical Vapor Deposition (LPCVD) technique. The concept of supersaturation was employed to control the morphology of NWs through the interplay between VLS and VS growth mechanisms. Comprehensive optical and material characterizations were carried out to evaluate the quality of the grown materials.
The growth of exceptionally high quality III-V phosphide NWs of InP and GaP was studied with an emphasis on the effects of vastly different sublimation rates of the associated III and V elements. The incorporation of defects exerted by deviation from stoichiometry was examined for GaP NWs, with an aim towards maximization of bandedge-to-defect emission ratio. In addition, a VLS-VS assisted growth of highly stoichiometric InP thin films and nano-networks with a wide temperature window from 560◦C to 720◦C was demonstrated. Such growth is shown to be insensitive to the type of substrates such as silicon, InP, and fused quartz. The dual gradient method was exploited to grow composition-graded ternary alloy NWs of InGaP, InGaAs, and GaAsP with different bandgaps ranging from 0.6 eV to 2.2 eV, to be used for making laterally-arrayed multiple bandgap (LAMB) solar cells. Furthermore, a template-based growth of the NWs was attempted based on the Si/SiO2 substrate. Such platform can be used to grow a wide range of alloy nanopillar materials, without being limited by typical lattice mismatch, providing a low cost universal platform for future PV solar cells.
ContributorsHashemi Amiri, Seyed Ebrahim (Author) / Ning, Cun-Zheng (Thesis advisor) / Petuskey, William (Committee member) / Yu, Hongbin (Committee member) / Arizona State University (Publisher)
Created2018
Description
Recently, nanostructured metamaterials have attracted lots of attentions due to its tunable artificial properties. In particular, nanowire
anohole based metamaterials which are known of the capability of large area fabrication were intensively studied. Most of the studies are only based on the electrical responses of the metamaterials; however, magnetic response, is usually neglected since magnetic material does not exist naturally within the visible or infrared range. For the past few years, artificial magnetic response from nanostructure based metamaterials has been proposed. This reveals the possibility of exciting resonance modes based on magnetic responses in nanowire
anohole metamaterials which can potentially provide additional enhancement on radiative transport. On the other hand, beyond classical far-field radiative heat transfer, near-field radiation which is known of exceeding the Planck’s blackbody limit has also become a hot topic in the field.
This PhD dissertation aims to obtain a deep fundamental understanding of nanowire
anohole based metamaterials in both far-field and near-field in terms of both electrical and magnetic responses. The underlying mechanisms that can be excited by nanowire
anohole metamaterials such as electrical surface plasmon polariton, magnetic hyperbolic mode, magnetic polariton, etc., will be theoretically studied in both far-field and near-field. Furthermore, other than conventional effective medium theory which only considers the electrical response of metamaterials, the artificial magnetic response of metamaterials will also be studied through parameter retrieval of far-field optical and radiative properties for studying near-field radiative transport. Moreover, a custom-made AFM tip based metrology will be employed to experimentally study near-field radiative transfer between a plate and a sphere separated by nanometer vacuum gaps in vacuum. This transformative research will break new ground in nanoscale radiative heat transfer for various applications in energy systems, thermal management, and thermal imaging and sensing.
anohole based metamaterials which are known of the capability of large area fabrication were intensively studied. Most of the studies are only based on the electrical responses of the metamaterials; however, magnetic response, is usually neglected since magnetic material does not exist naturally within the visible or infrared range. For the past few years, artificial magnetic response from nanostructure based metamaterials has been proposed. This reveals the possibility of exciting resonance modes based on magnetic responses in nanowire
anohole metamaterials which can potentially provide additional enhancement on radiative transport. On the other hand, beyond classical far-field radiative heat transfer, near-field radiation which is known of exceeding the Planck’s blackbody limit has also become a hot topic in the field.
This PhD dissertation aims to obtain a deep fundamental understanding of nanowire
anohole based metamaterials in both far-field and near-field in terms of both electrical and magnetic responses. The underlying mechanisms that can be excited by nanowire
anohole metamaterials such as electrical surface plasmon polariton, magnetic hyperbolic mode, magnetic polariton, etc., will be theoretically studied in both far-field and near-field. Furthermore, other than conventional effective medium theory which only considers the electrical response of metamaterials, the artificial magnetic response of metamaterials will also be studied through parameter retrieval of far-field optical and radiative properties for studying near-field radiative transport. Moreover, a custom-made AFM tip based metrology will be employed to experimentally study near-field radiative transfer between a plate and a sphere separated by nanometer vacuum gaps in vacuum. This transformative research will break new ground in nanoscale radiative heat transfer for various applications in energy systems, thermal management, and thermal imaging and sensing.
ContributorsChang, Jui-Yung (Author) / Wang, Liping (Thesis advisor) / Phelan, Patrick (Committee member) / Wang, Robert (Committee member) / Yu, Hongbin (Committee member) / Hildreth, Owen (Committee member) / Arizona State University (Publisher)
Created2017