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- All Subjects: nanotechnology
- Creators: Kozicki, Michael
- Creators: Tongay, Sefaattin
- Resource Type: Text
- Status: Published
Description
Programmable Metallization Cell (PMC) is a technology platform which utilizes mass transport in solid or liquid electrolyte coupled with electrochemical (redox) reactions to form or remove nanoscale metallic electrodeposits on or in the electrolyte. The ability to redistribute metal mass and form metallic nanostructure in or on a structure in situ, via the application of a bias on laterally placed electrodes, creates a large number of promising applications. A novel PMC-based lateral microwave switch was fabricated and characterized for use in microwave systems. It has demonstrated low insertion loss, high isolation, low voltage operation, low power and low energy consumption, and excellent linearity. Due to its non-volatile nature the switch operates with fewer biases and its simple planar geometry makes possible innovative device structures which can be potentially integrated into microwave power distribution circuits. PMC technology is also used to develop lateral dendritic metal electrodes. A lateral metallic dendritic network can be grown in a solid electrolyte (GeSe) or electrodeposited on SiO2 or Si using a water-mediated method. These dendritic electrodes grown in a solid electrolyte (GeSe) can be used to lower resistances for applications like self-healing interconnects despite its relatively low light transparency; while the dendritic electrodes grown using water-mediated method can be potentially integrated into solar cell applications, like replacing conventional Ag screen-printed top electrodes as they not only reduce resistances but also are highly transparent. This research effort also laid a solid foundation for developing dendritic plasmonic structures. A PMC-based lateral dendritic plasmonic structure is a device that has metallic dendritic networks grown electrochemically on SiO2 with a thin layer of surface metal nanoparticles in liquid electrolyte. These structures increase the distribution of particle sizes by connecting pre-deposited Ag nanoparticles into fractal structures and result in three significant effects, resonance red-shift, resonance broadening and resonance enhancement, on surface plasmon resonance for light trapping simultaneously, which can potentially enhance thin film solar cells' performance at longer wavelengths.
ContributorsRen, Minghan (Author) / Kozicki, Michael (Thesis advisor) / Schroder, Dieter (Committee member) / Roedel, Ronald (Committee member) / Barnaby, Hugh (Committee member) / Arizona State University (Publisher)
Created2011
Description
Carbon nanomaterials have caught tremendous attention in the last few decades due to their unique physical and chemical properties. Tremendous effort has been made to develop new synthesis techniques for carbon nanomaterials and investigate their properties for different applications. In this work, carbon nanospheres (CNSs), carbon foams (CF), and single-walled carbon nanotubes (SWNTs) were studied for various applications, including water treatment, energy storage, actuators, and sensors.
A facile spray pyrolysis synthesis technique was developed to synthesize individual CNSs with specific surface area (SSA) up to 1106 m2/g. The hollow CNSs showed adsorption of up to 300 mg rhodamine B dye per gram carbon, which is more than 15 times higher than that observed for conventional carbon black. They were also evaluated as adsorbents for removal of arsenate and selenate from water and displayed good binding to both species, outperforming commercial activated carbons for arsenate removal in pH > 8. When evaluated as supercapacitor electrode materials, specific capacitances of up to 112 F/g at a current density of 0.1 A/g were observed. When used as Li-ion battery anode materials, the CNSs achieved a discharge capacity of 270 mAh/g at a current density of 372 mA/g (1C), which is 4-fold higher than that of commercial graphite anode.
Carbon foams were synthesized using direct pyrolysis and had SSA up to 2340 m2/g. When used as supercapacitor electrode materials, a specific capacitance up to 280 F/g was achieved at current density of 0.1 A/g and remained as high as 207 F/g, even at a high current density of 10 A/g.
A printed walking robot was made from common plastic films and coatings of SWNTs. The solid-state thermal bimorph actuators were multifunctional energy transducers powered by heat, light, or electricity. The actuators were also investigated for photo/thermal detection. Electrochemical actuators based on MnO2 were also studied for potential underwater applications.
SWNTs were also used to fabricate printable electrodes for trace Cr(VI) detection, which displayed sensitivity up to 500 nA/ppb for Cr(VI). The limit of detection was shown to be as low as 5 ppb. A flow detection system based on CNT/printed electrodes was also demonstrated.
A facile spray pyrolysis synthesis technique was developed to synthesize individual CNSs with specific surface area (SSA) up to 1106 m2/g. The hollow CNSs showed adsorption of up to 300 mg rhodamine B dye per gram carbon, which is more than 15 times higher than that observed for conventional carbon black. They were also evaluated as adsorbents for removal of arsenate and selenate from water and displayed good binding to both species, outperforming commercial activated carbons for arsenate removal in pH > 8. When evaluated as supercapacitor electrode materials, specific capacitances of up to 112 F/g at a current density of 0.1 A/g were observed. When used as Li-ion battery anode materials, the CNSs achieved a discharge capacity of 270 mAh/g at a current density of 372 mA/g (1C), which is 4-fold higher than that of commercial graphite anode.
Carbon foams were synthesized using direct pyrolysis and had SSA up to 2340 m2/g. When used as supercapacitor electrode materials, a specific capacitance up to 280 F/g was achieved at current density of 0.1 A/g and remained as high as 207 F/g, even at a high current density of 10 A/g.
A printed walking robot was made from common plastic films and coatings of SWNTs. The solid-state thermal bimorph actuators were multifunctional energy transducers powered by heat, light, or electricity. The actuators were also investigated for photo/thermal detection. Electrochemical actuators based on MnO2 were also studied for potential underwater applications.
SWNTs were also used to fabricate printable electrodes for trace Cr(VI) detection, which displayed sensitivity up to 500 nA/ppb for Cr(VI). The limit of detection was shown to be as low as 5 ppb. A flow detection system based on CNT/printed electrodes was also demonstrated.
ContributorsWang, Chengwei, Ph.D (Author) / Chan, Candace K. (Thesis advisor) / Tongay, Sefaattin (Committee member) / Wang, Qing Hua (Committee member) / Seo, Dong (Committee member) / Arizona State University (Publisher)
Created2015
Description
In the nano-regime many materials exhibit properties that are quite different from their bulk counterparts. These nano-properties have been shown to be useful in a wide range of applications with nanomaterials being used for catalysts, in energy production, as protective coatings, and in medical treatment. While there is no shortage of exciting and novel applications, the world of nanomaterials suffers from a lack of large scale manufacturing techniques. The current methods and equipment used for manufacturing nanomaterials are generally slow, expensive, potentially dangerous, and material specific. The research and widespread use of nanomaterials has undoubtedly been hindered by this lack of appropriate tooling. This work details the effort to create a novel nanomaterial synthesis and deposition platform capable of operating at industrial level rates and reliability.
The tool, referred to as Deppy, deposits material via hypersonic impaction, a two chamber process that takes advantage of compressible fluids operating in the choked flow regime to accelerate particles to up several thousand meters per second before they impact and stick to the substrate. This allows for the energetic separation of the synthesis and deposition processes while still behaving as a continuous flow reactor giving Deppy the unique ability to independently control the particle properties and the deposited film properties. While the ultimate goal is to design a tool capable of producing a broad range of nanomaterial films, this work will showcase Deppy's ability to produce silicon nano-particle films as a proof of concept.
By adjusting parameters in the upstream chamber the particle composition was varied from completely amorphous to highly crystalline as confirmed by Raman spectroscopy. By adjusting parameters in the downstream chamber significant variation of the film's density was achieved. Further it was shown that the system is capable of making these adjustments in each chamber without affecting the operation of the other.
The tool, referred to as Deppy, deposits material via hypersonic impaction, a two chamber process that takes advantage of compressible fluids operating in the choked flow regime to accelerate particles to up several thousand meters per second before they impact and stick to the substrate. This allows for the energetic separation of the synthesis and deposition processes while still behaving as a continuous flow reactor giving Deppy the unique ability to independently control the particle properties and the deposited film properties. While the ultimate goal is to design a tool capable of producing a broad range of nanomaterial films, this work will showcase Deppy's ability to produce silicon nano-particle films as a proof of concept.
By adjusting parameters in the upstream chamber the particle composition was varied from completely amorphous to highly crystalline as confirmed by Raman spectroscopy. By adjusting parameters in the downstream chamber significant variation of the film's density was achieved. Further it was shown that the system is capable of making these adjustments in each chamber without affecting the operation of the other.
ContributorsFirth, Peter (Author) / Holman, Zachary C (Thesis advisor) / Kozicki, Michael (Committee member) / Goryll, Michael (Committee member) / Arizona State University (Publisher)
Created2015
Description
In competitive Taekwondo, Electronic Body Protectors (EBPs) are used to register hits made by players during sparring. EBPs are comprised of three main components: chest guard, foot sock, and headgear. This equipment interacts with each other through the use of magnets, electric sensors, transmitters, and a receiver. The receiver is connected to a computer programmed with software to process signals from the transmitter and determine whether or not a competitor scored a point. The current design of EBPs, however, have numerous shortcomings, including sensing false positives, failing to register hits, costing too much, and relying on human judgment. This thesis will thoroughly delineate the operation of the current EBPs used and discuss research performed in order to eliminate these weaknesses.
ContributorsSpell, Valerie Anne (Author) / Kozicki, Michael (Thesis director) / Kitchen, Jennifer (Committee member) / Electrical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Graphene is a very strong two-dimensional material with a lot of potential applications in microelectromechanical systems (MEMS). In this research, graphene is being optimized for use in a 5 m x 5 m graphene resonator. To work properly, this graphene resonator must have a uniform strain across all manufactured devices. To reduce strain induced in graphene sheets grown for use in these resonators, evaporated platinum has been used in this investigation due to its relatively lower surface roughness compared to copper films. The final goal is to have the layer of ultrathin platinum (<=200 nm) deposited on the MEMS graphene resonator and used to grow graphene directly onto the devices to remove the manual transfer step due to its inscalability. After growth, graphene is coated with polymer and the platinum is then etched. This investigation concentrated on the transfer process of graphene onto Si/SiO2 substrate from the platinum films. It was determined that the ideal platinum etchant was aqua regia at a volumetric ratio of 6:3:1 (H2O:HCl:HNO3). This concentration was dilute enough to preserve the polymer and graphene layer, but strong enough to etch within a day. Type and thickness of polymer support layers were also investigated. PMMA at a thickness of 200 nm was ideal because it was easy to remove with acetone and strong enough to support the graphene during the etch process. A reference growth recipe was used in this investigation, but now that the transfer has been demonstrated, growth can be optimized for even thinner films.
ContributorsCayll, David Richard (Author) / Tongay, Sefaattin (Thesis director) / Lee, Hyunglae (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
The proposed research mainly focuses on employing tunable materials to achieve dynamic control of radiative heat transfer in both far and near fields for thermal management. Vanadium dioxide (VO2), which undergoes a phase transition from insulator to metal at the temperature of 341 K, is one tunable material being applied. The other one is graphene, whose optical properties can be tuned by chemical potential through external bias or chemical doping.
In the far field, a VO2-based metamaterial thermal emitter with switchable emittance in the mid-infrared has been theoretically studied. When VO2 is in the insulating phase, high emittance is observed at the resonance frequency of magnetic polaritons (MPs), while the structure becomes highly reflective when VO2 turns metallic. A VO2-based thermal emitter with tunable emittance is also demonstrated due to the excitation of MP at different resonance frequencies when VO2 changes phase. Moreover, an infrared thermal emitter made of graphene-covered SiC grating could achieve frequency-tunable emittance peak via the change of the graphene chemical potential.
In the near field, a radiation-based thermal rectifier is constructed by investigating radiative transfer between VO2 and SiO2 separated by nanometer vacuum gap distances. Compared to the case where VO2 is set as the emitter at 400 K as a metal, when VO2 is considered as the receiver at 300 K as an insulator, the energy transfer is greatly enhanced due to the strong surface phonon polariton (SPhP) coupling between insulating VO2 and SiO2. A radiation-based thermal switch is also explored by setting VO2 as both the emitter and the receiver. When both VO2 emitter and receiver are at the insulating phase, the switch is at the “on” mode with a much enhanced heat flux due to strong SPhP coupling, while the near-field radiative transfer is greatly suppressed when the emitting VO2 becomes metallic at temperatures higher than 341K during the “off” mode. In addition, an electrically-gated thermal modulator made of graphene covered SiC plates is theoretically studied with modulated radiative transport by varying graphene chemical potential. Moreover, the MP effect on near-field radiative transport has been investigated by spectrally enhancing radiative heat transfer between two metal gratings.
In the far field, a VO2-based metamaterial thermal emitter with switchable emittance in the mid-infrared has been theoretically studied. When VO2 is in the insulating phase, high emittance is observed at the resonance frequency of magnetic polaritons (MPs), while the structure becomes highly reflective when VO2 turns metallic. A VO2-based thermal emitter with tunable emittance is also demonstrated due to the excitation of MP at different resonance frequencies when VO2 changes phase. Moreover, an infrared thermal emitter made of graphene-covered SiC grating could achieve frequency-tunable emittance peak via the change of the graphene chemical potential.
In the near field, a radiation-based thermal rectifier is constructed by investigating radiative transfer between VO2 and SiO2 separated by nanometer vacuum gap distances. Compared to the case where VO2 is set as the emitter at 400 K as a metal, when VO2 is considered as the receiver at 300 K as an insulator, the energy transfer is greatly enhanced due to the strong surface phonon polariton (SPhP) coupling between insulating VO2 and SiO2. A radiation-based thermal switch is also explored by setting VO2 as both the emitter and the receiver. When both VO2 emitter and receiver are at the insulating phase, the switch is at the “on” mode with a much enhanced heat flux due to strong SPhP coupling, while the near-field radiative transfer is greatly suppressed when the emitting VO2 becomes metallic at temperatures higher than 341K during the “off” mode. In addition, an electrically-gated thermal modulator made of graphene covered SiC plates is theoretically studied with modulated radiative transport by varying graphene chemical potential. Moreover, the MP effect on near-field radiative transport has been investigated by spectrally enhancing radiative heat transfer between two metal gratings.
ContributorsYang, Yue (Author) / Wang, Liping (Thesis advisor) / Phelan, Patrick (Committee member) / Wang, Robert (Committee member) / Tongay, Sefaattin (Committee member) / Rykaczewski, Konrad (Committee member) / Arizona State University (Publisher)
Created2016
Description
Nanomaterials exhibit unique properties that are substantially different from their bulk counterparts. These unique properties have gained recognition and application for various fields and products including sensors, displays, photovoltaics, and energy storage devices. Aerosol Deposition (AD) is a relatively new method for depositing nanomaterials. AD utilizes a nozzle to accelerate the nanomaterial into a deposition chamber under near-vacuum conditions towards a substrate with which the nanomaterial collides and adheres. Traditional methods for designing nozzles at atmospheric conditions are not well suited for nozzle design for AD methods.
Computational Fluid Dynamics (CFD) software, ANSYS Fluent, is utilized to simulate two-phase flows consisting of a carrier gas (Helium) and silicon nanoparticles. The Cunningham Correction Factor is used to account for non-continuous effects at the relatively low pressures utilized in AD.
The nozzle, referred to herein as a boundary layer compensation (BLC) nozzle, comprises an area-ratio which is larger than traditionally designed nozzles to compensate for the thick boundary layer which forms within the viscosity-affected carrier gas flow. As a result, nanoparticles impact the substrate at velocities up to 300 times faster than the baseline nozzle.
Computational Fluid Dynamics (CFD) software, ANSYS Fluent, is utilized to simulate two-phase flows consisting of a carrier gas (Helium) and silicon nanoparticles. The Cunningham Correction Factor is used to account for non-continuous effects at the relatively low pressures utilized in AD.
The nozzle, referred to herein as a boundary layer compensation (BLC) nozzle, comprises an area-ratio which is larger than traditionally designed nozzles to compensate for the thick boundary layer which forms within the viscosity-affected carrier gas flow. As a result, nanoparticles impact the substrate at velocities up to 300 times faster than the baseline nozzle.
ContributorsHoffman, Trent (Author) / Holman, Zachary C (Thesis advisor) / Herrmann, Marcus (Committee member) / Kozicki, Michael (Committee member) / Arizona State University (Publisher)
Created2017
Description
Counterfeiting of goods is a widespread epidemic that is affecting the world economy. The conventional labeling techniques are proving inadequate to thwart determined counterfeiters equipped with sophisticated technologies. There is a growing need of a secure labeling that is easy to manufacture and analyze but extremely difficult to copy. Programmable metallization cell technology operates on a principle of controllable reduction of a metal ions to an electrodeposit in a solid electrolyte by application of bias. The nature of metallic electrodeposit is unique for each instance of growth, moreover it has a treelike, bifurcating fractal structure with high information capacity. These qualities of the electrodeposit can be exploited to use it as a physical unclonable function. The secure labels made from the electrodeposits grown in radial structure can provide enhanced authentication and protection from counterfeiting and tampering.
So far only microscale radial structures and electrodeposits have been fabricated which limits their use to labeling only high value items due to high cost associated with their fabrication and analysis. Therefore, there is a need for a simple recipe for fabrication of macroscale structure that does not need sophisticated lithography tools and cleanroom environment. Moreover, the growth kinetics and material characteristics of such macroscale electrodeposits need to be investigated. In this thesis, a recipe for fabrication of centimeter scale radial structure for growing Ag electrodeposits using simple fabrication techniques was proposed. Fractal analysis of an electrodeposit suggested information capacity of 1.27 x 1019. The kinetics of growth were investigated by electrical characterization of the full cell and only solid electrolyte at different temperatures. It was found that mass transport of ions is the rate limiting process in the growth. Materials and optical characterization techniques revealed that the subtle relief like structure and consequently distinct optical response of the electrodeposit provides an added layer of security. Thus, the enormous information capacity, ease of fabrication and simplicity of analysis make macroscale fractal electrodeposits grown in radial programmable metallization cells excellent candidates for application as physical unclonable functions.
So far only microscale radial structures and electrodeposits have been fabricated which limits their use to labeling only high value items due to high cost associated with their fabrication and analysis. Therefore, there is a need for a simple recipe for fabrication of macroscale structure that does not need sophisticated lithography tools and cleanroom environment. Moreover, the growth kinetics and material characteristics of such macroscale electrodeposits need to be investigated. In this thesis, a recipe for fabrication of centimeter scale radial structure for growing Ag electrodeposits using simple fabrication techniques was proposed. Fractal analysis of an electrodeposit suggested information capacity of 1.27 x 1019. The kinetics of growth were investigated by electrical characterization of the full cell and only solid electrolyte at different temperatures. It was found that mass transport of ions is the rate limiting process in the growth. Materials and optical characterization techniques revealed that the subtle relief like structure and consequently distinct optical response of the electrodeposit provides an added layer of security. Thus, the enormous information capacity, ease of fabrication and simplicity of analysis make macroscale fractal electrodeposits grown in radial programmable metallization cells excellent candidates for application as physical unclonable functions.
ContributorsChamele, Ninad (Author) / Kozicki, Michael (Thesis advisor) / Barnaby, Hugh (Thesis advisor) / Newman, Nathan (Committee member) / Arizona State University (Publisher)
Created2017
Description
A Fundamental study of bulk, layered, and monolayers bromide lead perovskites structural, optical, and electrical properties have been studied as thickness changes. X-Ray Diffraction (XRD) and Raman spectroscopy measures the structural parameter showing how the difference in the thicknesses changes the crystal structures through observing changes in average lattice constant, atomic spacing, and lattice vibrations.
Optical and electrical properties have also been studied mainly focusing on the thickness effect on different properties where the Photoluminescence (PL) and exciton binding energies show energy shift as thickness of the material changes. Temperature dependent PL has shown different characteristics when comparing methylammonium lead bromide (MAPbBr3) to butylammonium lead bromide (BA2PbBr4) and comparing the two layered n=1 materials butylammonium lead bromide (BA2PbBr4) to butylammonium lead iodide (BA2PbI4). Time-resolved spectroscopy displays different lifetimes as thickness of bromide-based perovskite changes. Finally, thickness dependence (starting from monolayers) Kelvin Probe Force Microscopy (KPFM) of the layered materials BA2PbBr4, Butylammonium(methylammonium)lead bromide (BA2MAPb2Br7), and molybdenum sulfide (MoS2) were studied showing an exponential relation between the thickness of the materials and their surface potentials.
Optical and electrical properties have also been studied mainly focusing on the thickness effect on different properties where the Photoluminescence (PL) and exciton binding energies show energy shift as thickness of the material changes. Temperature dependent PL has shown different characteristics when comparing methylammonium lead bromide (MAPbBr3) to butylammonium lead bromide (BA2PbBr4) and comparing the two layered n=1 materials butylammonium lead bromide (BA2PbBr4) to butylammonium lead iodide (BA2PbI4). Time-resolved spectroscopy displays different lifetimes as thickness of bromide-based perovskite changes. Finally, thickness dependence (starting from monolayers) Kelvin Probe Force Microscopy (KPFM) of the layered materials BA2PbBr4, Butylammonium(methylammonium)lead bromide (BA2MAPb2Br7), and molybdenum sulfide (MoS2) were studied showing an exponential relation between the thickness of the materials and their surface potentials.
ContributorsAlenezi, Omar (Author) / Tongay, Sefaattin (Thesis advisor) / King, Richard (Thesis advisor) / Yao, Yu (Committee member) / Arizona State University (Publisher)
Created2019
Description
More recently there have been a tremendous advancement in theoretical studies showing remarkable properties that could be exploited from transition metal dichalcogenide (TMDC) Janus crystals through various applications. These Janus crystals are having a proven intrinsic electrical field due to breaking of out-of-plane inversion symmetry in a conventional TMDC when one of the chalcogenides atomic layer is being completely replaced by a layer of different chalcogen element. However, due to lack of accurate processing control at nanometer scales, key for creating a highly crystalline Janus structure has not yet been familiarized. Thus, experimental characterization and implication of these Janus crystals are still in a state of stagnation. This work presents a new advanced methodology that could prove to be highly efficient and effective for selective replacement of top layer atomic sites at room temperature conditions.
This is specifically more focused on proving an easy repeatability for replacement of top atomic layer chalcogenide from a parent structure of already grown TMDC monolayer (via CVD) by a post plasma processing technique. Though this developed technique is not limited to only chalcogen atom replacement but can be extended to any type of surface functionalization requirements.
Basic characterization has been performed on the Janus crystal of SeMoS and SeWS where, creation and characterization of SeWS has been done for the very first time, evidencing a repeatable nature of the developed methodology.
This is specifically more focused on proving an easy repeatability for replacement of top atomic layer chalcogenide from a parent structure of already grown TMDC monolayer (via CVD) by a post plasma processing technique. Though this developed technique is not limited to only chalcogen atom replacement but can be extended to any type of surface functionalization requirements.
Basic characterization has been performed on the Janus crystal of SeMoS and SeWS where, creation and characterization of SeWS has been done for the very first time, evidencing a repeatable nature of the developed methodology.
ContributorsTrivedi, Dipesh (Author) / Tongay, Sefaattin (Thesis advisor) / Green, Matthew (Committee member) / Zhuang, Houlong (Committee member) / Arizona State University (Publisher)
Created2019