James J. Watkins, Ph.D - US grants

Abstract - Watkins - 9734177 The demands of present and future microelectronic and optoelectronic device fabrication place stringent requirements on metal deposition schemes. These include high film purity, low temperatures and rapid, controllable deposition rates. The PI postulates that these objectives can be met via Chemical Fluid Deposition (CFD), a new approach to metal deposition that involves the chemical or thermal reduction of soluble organometallic compounds in supercritical carbon dioxide at low temperatures (40-80oC) to yield continuous films on inorganic or organic substrates. CFD exploits the unique, and adjustable, physicochemical properties of SCF solvents, which lie intermediate to those of liquids and gases, to circumvent the limitations of both vapor and liquid phase techniques. In CFD, precursor transport and reduction occurs in solution at significantly lower temperatures and higher reagent concentrations than those of vapor phase techniques such as chemical vapor deposition (CVD). While CFD is a solution-based process, the "gas-like" transport properties of the SCF and its miscibility with gaseous reducing agents such as hydrogen, render the process unencumbered by issues of poor mass transfer and poor deposition rates associated with liquid phase reductions. Preliminary experiments demonstrate that high-purity, continuous platinum and palladium films can be deposited from SCF solution onto silicon wafers and other inorganic substrates at temperatures up to 170oC below those employed in CVD. The research program will focus on the deposition of thin films from carbon dioxide solution by the hydrogenolysis of dimethylcyclooctadine platinum (II) and the deposition of copper films by reduction of copper(II)bis(hexafluoroacetylacetone) and copper(II)bis(2,2,6,6-tetramethyl-3,5-heptanedionate). The precursors were chosen to facilitate a direct comparison of film quality and reduction kinetics in CFD to those of existing techniques and the potential utility of the m etal deposits in microelectronics copper and catalytic platinum devices. The educational portion of the work are to: (1) train graduate students who will work at the interface of engineering and materials chemistry, (2) provide undergraduates with opportunities for research experience, (3) develop a two-course series in materials processing that addresses the interests of students and is reinforced by the expanding materials research efforts in the Department of Chemical Engineering, and (4) incorporate research problems and active learning principles into the classroom and assist in the implementation of interactive teaching tools across the curriculum.

Watkins - 9811088 The development of functional, nanostructured metal composite membranes will have a substantial economic impact on the separation, purification and recovery of gases as well as novel membrane reactor applications for oxygen-enriched combustion, controlled partial oxidation and equilibrium limited dehydrogenation reactions. Despite progress that has been achieved to date, precise control of deposit microstructure, composition and distribution within the support has not been realized. The challenge for porous-inorganic support/metal composites remains the development of methodologies for the controlled infiltration and deposition of nanostructured metal and metal alloys within interior pores at a prescribed depth and thickness. These architectures are inaccessible by current techniques including chemical vapor deposition, metal sputtering and electroless plating due to constraints of these processes that do not allow for optimization of deposit microstructure or composition. Polymer/metal composites membranes are plagued by poor and to rectify this deficiency, processes leading to gradient interfaces are required. The PI's plan to integrate materials synthesis, characterization and multi-scale simulations for the development of a processing strategy based on the concept of chemical fluid deposition (CFD). CFD is a form of metal deposition that involves the chemical reduction of soluble organometallic compounds in supercritical carbon dioxide solution. The key to the process is physicochemical properties of the solvent which lie intermediate to those of liquids and gases. Transport and reduction in solution offers low process temperatures, high reagent concentrations and eliminates precursor volatility requirements associated with vapor phase techniques. The absence of surface tension and low viscosity of supercritical fluid (SCF) solutions are well suited to the delivery of relatively high concentrations of organometallic precursors within porous environments. Deposi tion is triggered by the introduction of a reducing agent to produce metal deposits. This reaction scheme can be used to dictate deposit composition and microstructure via direct control of nucleation and growth kinetics by precise adjustments in stoichiometry of the soluble precursors. Mass-transport limitations are largely eliminated due to high precursor concentration and favorable transport properties of the SCF solution which is similar to those of a gas. The permeability of polymer substrates to SCF/organometallic solutions can be exploited to produce composite membranes with adherent, gradient polymer/metal interfaces and metal interlayers.

This award from the Major Research Instrumentation Program will allow the University of Massachusetts to purchase a x-ray photoelectron spectrometer (XPS) with integrated Auger analysis. The instrument will significantly enhance the capabilities of Interface Analysis Laboratory at UMass by providing high-resolution surface analysis and depth profiling capabilities that are currently lacking. The facility is accessible to the UMass community as well as research personnel from the surrounding Five College Community that includes Smith, Mt. Holyoke, Amherst and Hampshire Colleges and local industry. The Interface Analysis Laboratory and its director play an instrumental role in the support of broadly funded research programs in the chemical biological and materials sciences and for training of graduate and undergraduate students at these and other institutions. Specific programs include assessment of composition, contamination, interfacial properties and growth mechanisms for metal and semiconductor multi-layer films deposited from supercritical fluids, characterizing the chemical composition of polymer surfaces and interfaces modified to control interfacial interactions, surface wetting and biocompatability and the rational design of constrained-geometry catalysts for olefin polymerization.

This award from the Major Research Instrumentation Program will allow the University of Massachusetts to purchase a x-ray photoelectron spectrometer (XPS) with integrated Auger analysis. In tandem, XPS and Auger spectroscopy provide precise information regarding the atomic and molecular composition of surfaces that is crucial for the development and application of the advanced materials that are fueling today's economy. These include the assessment of metal and semiconductor films for microelectronic and photonic devices, the characterization of modified surfaces for consumer and medical applications, and the characterization of catalysts for more efficient fuel and chemical production. The instrument will be housed in an open Surface Analysis Facility that is easily accessible to the UMass Campus as well as research personnel from the surrounding Five College Community that includes Smith, Mt. Holyoke, Amherst and Hampshire Colleges and local industry. The facility plays an instrumental role in the training of graduate and undergraduate students at these and other institutions.

Research Objectives: A Multi-University/Industry/NIST team will address the development and integration of mesoporous, ultra-low dielectric constant films for semiconductor devices. Continuation of the historical trend of reduced device dimensions requires materials with dielectric constants (k) of less than 2.4 that can survive the structural and mechanical demands of integration. Moreover, at dimensions less than 70 nm, techniques that offer control over long range order, pore orientation and patterning at multiple length scales are required for practical integration schemes. A new approach offers these possibilities. The technique involves the infusion and selective condensation of metal oxide precursors within one domain of highly ordered block copolymer templates using supercritical (SC) carbon dioxide as the reaction medium. The template is then removed to produce the mesoporous oxide. By separating template preparation from oxide condensation, the block copolymer architecture can be manipulated at the local level by domain orientation and alignment using surface and external fields and at the device level by lithographic patterning prior to precursor infusion. Watkins (UMass) will coordinate the NIRT Team and lead the development of highly ordered mesoporous films in SC CO2. Ober (Cornell) will lead the development of templates for direct patterning by photolithography. Burkett (Amherst College) will characterize film structure and composition using solid state NMR. Maroudas (UMass) will develop models to relate film architecture to mechanical properties. Lin (NIST) will lead the development of new metrology tools for the analysis of patterned, highly ordered films. Schulberg from Novellus Systems, a leading semiconductor equipment company, will lead process development and scale-up efforts to full process wafers (200 and 300 mm) and develop post-processing strategies and integration schemes.

Broad Impact: Successful preparation of viable low k films will have an enormous near term impact on semiconductor manufacturing, a $100 billion/yr industry. The approach also provides a realizable technology platform for other metal oxide nanostructures including sensors, photonic materials, data storage arrays and separation media. Throughout the program, postdoctoral fellows, graduate and undergraduate students will acquire fundamental skills in a multidisciplinary environment that fosters an awareness of the demands of technology implementation. The partnership of a diverse team of PIs from Universities, Colleges, and Industry provides important opportunities for mentoring women and undergraduates from four-year institutions and advanced training of post-docs at the University/National Laboratory interface.

Research: The continuous drive towards smaller and more complex microelectronic devices is placing new demands on the fabrication technologies used for their production. One of the most difficult challenges is the rapid, defect-free deposition of high purity metals within narrow device features with dimensions below 100 nanometers. One prominent example of immediate concern is the fabrication of advanced copper interconnects for integrated circuits. With recent NSF funding, a fundamentally new technique that meets the performance criteria for device metallization, called supercritical fluid deposition (SFD), was developed at the University of Massachusetts. In SFD, soluble organometallic compounds are reduced in supercritical fluids including carbon dioxide to yield high purity deposits at low temperature. A supercritical fluid can be viewed as hybrid medium with properties that lie intermediate to those of gases and liquids. These properties are such that the limitations of current liquid and vapor-phase techniques can be circumvented while preserving the benefits of each. The result for Cu deposition is unprecedented feature fill at sub-100 nm device dimensions, while maintaining other critical film properties.

The PI's results to date indicate SFD offers great promise for the fabrication of semiconductor and other devices, but the technique is still in its infancy and fundamental studies are required to further development and broaden its impact. Toward this end, the PI will examine two issues that are essential to understanding SFD and related SCF processes. First, the mechanisms for SFD reactions will be determined and models that capture both deposition kinetics and step coverage will be elucidated. Knowledge of reaction pathways during SFD will have direct implications for device metallization and broader impact for catalytic reactions in supercritical media. Second, computation fluid dynamics (CFD) simulations will be developed to describe heat and mass transfer in multi-component supercritical deposition reactors under highly turbulent flow. These capabilities are not accessible in commercial packages and will be invaluable for a broad range of SCF applications. Experimental data will be used to validate and refine the models.

Impact: The research program is a cooperative effort between the University of Massachusetts and Novellus Systems, a leading semiconductor equipment company that has licensed SFD for microelectronic applications. It will facilitate the development of SFD for interconnect technology, which may prove enabling for future generations of integrated circuits, a $100 billion / yr. industry. Success will result in the transfer of academic research to commercial applications while eliciting fundamentals of reaction and transport in SCFs that have broad relevance to a number key industries. The program will also provide a unique opportunity for graduate students to work at the interface of industry and academia.

This Integrative Graduate Education and Research Training (IGERT) award supports interdisciplinary doctoral training in nanotechnology at the University of Massachusetts Amherst. The research and education activities span six science and engineering departments using a structure that ties advances in fundamental science to complementary coursework and practical experience in innovation and technology development. The program's intellectual merit and research emphasis is on the design, prototyping and market-oriented development of nanoscale devices through seamless integration of novel bottom-up processing schemes, including self-assembly, with conventional top-down approaches. Doctoral training is centered around three related research thrusts: nanoscale materials and processes; electronic applications; and biomedical and environmental applications. Specifically, IGERT students conduct research on the directed self-assembly of block copolymers, advanced lithography, novel deposition and metallization techniques, and their implementation in nanoelectronic devices, high-density data storage, biosensors and therapeutics. In addition to multidisciplinary technical, professional and product development training, the students team-train on annual Technical Challenge Projects that develop their ability to design and prototype technically and commercially feasible devices using nanotechnology. These projects include external research experiences at R&D facilities and fabrication centers located in the U.S. and abroad. Collaborators and advisors for the projects include TIAX and Lucent Technologies' Bell Laboratories. Additional activities focus on ethics, leadership and communication. The program's broader impacts include developing scientists and engineers that are comfortable working at disciplinary boundaries, possess a well-rounded mastery of nanoscience and engineering and have the ability to transform advances in basic science to functional materials and devices that can be commercialized to meet emerging technological and societal needs. IGERT is an NSF-wide program intended to meet the challenges of educating U.S. Ph.D. scientists and engineers with the interdisciplinary background, deep knowledge in a chosen discipline, and the technical, professional, and personal skills needed for the career demands of the future. The program is intended to catalyze a cultural change in graduate education by establishing innovative new models for graduate education and training in a fertile environment for collaborative research that transcends traditional disciplinary boundaries.

The establishment of a Nano-Imprint Lithography (NIL) Laboratory on the campus of the University of Massachusetts Amherst will permit the definition of material patterns from the multi-micron to sub-50nm length scales in an economical and efficient manner. The rapid replication and prototyping provided by this technique will enable the study of devices and structures that would otherwise be difficult or prohibitively expensive to make. NIL involves 1) the physical templating of topographic or chemical structures and 2) subsequent photo- or thermal-initiated materials synthesis. The full implementation of this laboratory requires the purchase of two instruments for which we are requesting funding: a Step-and-Flash NIL instrument from Molecular Imprints, Inc. and a state-of-the-art plasma etching system from Trion, Inc. This laboratory is critical to the success of multiple research activities involving the co-PIs and other members of the NSF MRSEC at UMass including the development of advanced materials for nanostructured devices (e.g. nanoscale patterned surfaces for sensors, single-step processing of ultra-low dielectric constant patterns, and high power density pulsed power capacitors for electric vehicles) and fundamental research into the challenges that are limiting the implementation of NIL on the manufacturing scale. The instruments will be housed in the open access Keck Nanostructures Laboratory and a comprehensive management plan is in place to ensure maintenance and accessibility to a broad user base. Additionally, the NIL Laboratory will be incorporated into existing courses on nanotechnology, and its open-access management plan will encourage use by participants in our REU and RET programs as well as faculty and students in the local five college community that includes two women's colleges: Mt. Holyoke College and Smith College. UMass Amherst is an established leader in nanoscale materials science, and this facility will further secure our leadership in device-level implementation of our discoveries while preparing students with expertise in real-world nano-scale manufacturing.


This award at the University of Massachusetts Amherst will allow researchers on campus, as well as researchers in the local community and beyond, to advance and expand their expertise in materials research at sizes smaller than one-billionth of a meter. This grant will fund the purchase of two advanced technology instruments that together will enable the preparation of materials with user-defined patterns that are 1000 times smaller than the diameter of a human hair. This capability will aid in the development of new technologies such as chemical sensors, faster and more stable computer chips, and power management devices for electric vehicles. This facility will be an open-access center for faculty and students at UMass and in the local college community which includes two women's colleges: Mt. Holyoke College and Smith College. A comprehensive management plan will ensure accessibility, maintenance, and the incorporation of these instruments into materials research courses, while encouraging non-traditional researchers involved in the Research Experience for Undergraduates and Research Experience for Teachers outreach programs to use the laboratory. UMass currently has a number of exciting initiatives in nanotechnology, and the establishment of this Laboratory will ensure that we remain at the forefront of cutting edge research.

ABSTRACT

PI: James J. Watkins
Institution: University of Massachusetts/Amherst
Proposal Number: 0529034
Title: Sensors: Hierarchical Metal Oxides for Next Generation Devices

The ability to control the structure and surface properties of hierarchical metal oxides across length scales ranging from a few nanometers to several centimeters offers the promise of next generation sensors with dramatically improved sensitivity, selectivity and response time. Realization of that potential, however, requires the development of efficient fabrication strategies that enable prescriptive control over the size, structure, and orientation of nanometer scale pores and provide the ability to control surface chemistry and placement of functional elements within these structures. Target structures include defect free silica, alumina and titania films containing well-ordered spherical pores and close-packed arrays of uniform, functionalized cylindrical pores of prescribed diameter oriented normal to substrate in these materials. The latter elements offer not only large surface to volume ratios, but also short and unencumbered diffusion paths for analytes and thin pore walls such that their electronic properties are strongly influenced by surface processes, a key to high sensitivity. Finally, a fabrication scheme that can be integrated directly into existing device fabrication lines is required for high volume production. The PI has developed a new approach for mesoporous oxides that can achieve these objectives.

His approach involves the phase-selective condensation of metal alkoxides within specific sub-domains of pre-organized block copolymer template films dilated with supercritical carbon dioxide. Subsequent removal of the template yields a well-ordered mesoporous solid that retains all of the structural detail of microphase separated block copolymers. Recently he validated this approach for the preparation of device-quality silicate films on full process Si wafers for application as ultra low dielectric constant films. Here he exploits enabling aspects of the 3-D replication process to produce hierarchical silica, titania and alumina films as constructs for sensor applications. These include (1) the separation of template organization from metal oxide network formation, which provides flexible process chemistry through independent selection of template and precursor and removes constraints associated with cooperative selfassembly, (2) the use of a non-aqueous reaction media that is compatible with hydrolytically sensitive precursors for titania, alumina and other metal oxides, and (3) manipulation of block copolymer architecture by domain orientation and alignment prior to precursor infusion, which enables the production of nanochannel arrays of cylindrical pores oriented normal to the substrate surface with tunable pore diameters. Once the metal oxide framework is in place, control of surface chemistry is essential for maximizing sensor performance. The transport properties of supercritical CO2 offer distinct advantages for surface modifications using organosilanes and hydridosilane chemistry within nanostructured oxides. In addition to controlling the hydrophilic/hydrophobic character of the substrate surface, these modifications can provide reactive handles for immobilization of enzymes and metal clusters on the pore walls. Finally, doping the templates with active species prior to precursor infusion provides an alternative route to functionalizing the metal oxides by encapsulation.

Technical Merit: The scientific core is the development of a rapid and efficient route for the preparation of functionalized hierarchical metal oxides as a platform for nanosensor device applications. Successful replication of block copolymer morphologies to yield well-ordered mesoporous titania and alumina films, including control of pore orientation and pore dimensions would represent a significant advance in materials science. The fabrication of nanochannel arrays in silicates, alumina and titania with pores of defined size, ranging between 10 and 45 nm, presents an optimal substrate for enhancing the performance of broad classes of sensors.

Broader Impacts: The development of well-defined metal oxide films with nanometer-scale periodicity is of interest for numerous applications including catalysis, separations, microfluidics, energy conversion and low dielectric constant films in microelectronics. An efficient and general means for their production would have broad impact. For example, nanochannel arrays in titania similar to those produced here for sensors would be ideal for the fabrication of high surface area heterojunctions for conjugated polymer photovoltaic cells, while well-ordered silicates containing immobilized enzymes or highly-dispersed metal clusters would have certain application in catalysis. The project will expose graduate students to interdisciplinary research and involve the participation of undergraduate students. Project results will be put in modular form for use in existing curriculum including a survey course in nanotechnology and an undergraduate laboratory course and used as an example of applications of nanotechnology during secondary school visits hosted by MassNanoTech on the UMass Amherst campus.

This Nanoscale Science and Engineering Center (NSEC) is a comprehensive research and education platform that will stimulate U.S. competitiveness by moving nanotechnology from laboratory innovation to manufacturable nanostructured components and devices. The Center for Hierarchical Manufacturing builds on recognized excellence in nanoscience and technology at UMass and a world-class program in polymer research to yield complete specification of nanostructures combining directed self-assembly and imprinting with subsequent transfer of 2-D and 3-D structures, and advanced deposition techniques, into active components, functional materials, and fully-integrated devices. Bottom-up processes will be seamlessly integrated with conventional fabrication methods for dramatic advances in semiconductor devices, microelectronics, biomedical applications, and other areas. In addition, the Center offers a new strategic model to bridge the innovation-to-implementation gap through test beds that combine leading breakthrough technology, professional market analysis, industrial-scale fabrication processes, and facilitated technology transfer.

The impact of this Center is strengthened through strong collaborators including leading R&D consultant TIAX and prototyping partner Lucent Technologies will allow the Center to drive concepts to commercialization. Students educated in this environment will be well prepared for careers that partner innovation with implementation. The Center initiates a National Nanomanufacturing Network (NNN)--a catalyst for U.S. nanomanufacturing-based economic development, a network of shared manufacturing facilities, a dynamic web-based information clearinghouse, and a pathway for university-industry-government partnerships. The NNN will integrate and amplify the impact of all NSECs and the nanomanufacturing research community. The Center will address a national need by creating and disseminating research-based multimedia instructional materials to stimulate and educate audiences ranging from K-12 students and teachers, community college learners, and the public. A strong societal implications program includes national workshops and survey studies. The Center's efforts are leveraged by strong commitments from the University of Massachusetts Amherst and the Commonwealth of Massachusetts.

This NSF award to University of Massachusetts Amherst funds U.S. researchers participating in a project competitively selected by the G8 Research Councils Initiative ?Structural Bamboo Products.? This is a pilot collaboration among the U.S. National Science Foundation, the Canadian National Sciences and Engineering Research Council (NSERC), the French Agence Nationale de la Recherche (ANR), the German Deutsche Forschungsgemeinschaft (DFG), the Japan Society for the Promotion of Science (JSPS), the Russian Foundation for Basic Research (RFBR),and the United Kingdom Research Councils (RCUK), supporting collaborative research projects selected on a competitive basis that are comprised of researchers from at least three of the partner countries.

This multi-national collaboration--Methods for Materials-efficient Manufacturing (M3)-- will perform research on polymer-nanoparticle hybrid materials for sustainable production of advanced technology devices. The M3 team includes the University of Massachusetts Amherst and Rutgers University (U.S.), Tohoku University and the University of Tokyo (Japan), and Institut de Chimie de la Matière condensée de Bordeaux and the UMR CNRS Environnement, Ville, Société (France). The M3 research program focuses on solution-based processing of devices, device layers, components and functional materials on a roll-to-roll production platform, in which hybrid materials containing both polymers and nanoparticles are used to generate functional devices on flexible substrates. One technical goal for the project is development of solution-coatable high dielectric constant device layers comprised of polymer/nanoparticle composites; these layers are the active components of working devices, and progress in this field will advance efficient roll-to-roll flexible device production. A second technical goal is the use of polymer/nanoparticle solutions to form highly transparent emissive nanocomposite films containing optically active nanoparticles, including rare-earth dopes phosphors, as the functional component. U.S. research activities focus on developing the polymer hybrid materials and roll-to-roll processing methods (UMass Amherst), and synthesizing and characterizing the optically active composites (Rutgers).

The outcomes from this multinational research project will lead to more materials-efficient and sustainable manufacturing of materials and devices for applications such as energy conversion and storage, flexible electronics and displays, and optoelectronics. Compared to conventional batch vacuum and deposition processes, the solution-based roll-to-roll process can afford lower cost, less waste and significantly lower energy inputs. When combined with innovations in the materials used in the coating process for device fabrication, it is expected that the resultant process will involve fewer steps, no batch changes, commodity-priced materials, lower process temperatures, and drastically lower water usage, thereby reducing direct energy consumption.

The broader impact/commercial potential of this I-Corps project is to deliver a low cost mastering technology to enable the cost-effective pattering of polymer and other surfaces to impart function without the use of chemical additives. The masters will be used in microreplication, injection molding and embossing to impart structural color, antimicrobial activity, anti-counterfeiting marks, light collection for solar energy and other surface functionality with high yield and high throughput, impacting consumer products and technology companies alike. The use of surface patterns as opposed to chemical additives to achieve function offers environmental and consumer safety advantages and is resource and energy efficient.

This I-Corps project employs a fundamentally new approach to the fabrication of master molds for patterning polymer surfaces via microreplication and nanoreplication technologies including injection molding, nanoimprint lithography, and embossing. Master molds are typically produced via optical lithography and etching of rigid substrates including silicon wafers, stainless steel and quartz, which is expensive as well as time and resource intensive. This is a novel process for direct imprinting of dimensionally stable crystalline metal oxide nanostructures that are fabricated using soft lithography with inks comprised of crystalline nanoparticles. Via this process it is possible to create a soft daughter mold from a single parent master and use that soft mold to create successive generations of high fidelity, robust masters in crystalline zirconia and other metal oxides, substantially reducing cost. In addition the use of zirconia patterns on thermally robust master substrates enables pattern transfer at temperatures far above those accessible using conventional masters.

The broader impact/commercial potential of this Partnerships for Innovation – Research Partnerships (PFI-RP) project is the design and fabrication of high performance metalenses using an innovative, cost-effective approach that will enable a superior product that cannot otherwise be manufactured in a scalable manner. Metalenses (or flat lenses) are ultrathin planar lenses that use nanofeatures patterned on the surface to efficiently control light. thereby eliminating the bulkiness of traditional glass and plastic lenses while providing more utility and function in a substantially lighter and smaller volume. Lens miniaturization and the introduction of wide fields of view and corrections for distortion and color aberration, all possible with metalenses, have enormous economic potential for consumer products, medical, defense, and space applications. Technology insertion points include cell phone cameras, augmented reality / virtual reality (AR/VR), heads-up displays, medical and scientific imaging, precision optics, and high-resolution imaging satellites, with associated markets exceeding $100 billion. The PFI RP team addresses the critical elements of the supply and technology chains enabling domestic commercialization of an emerging technology with substantial societal impact.

The proposed project is a novel but achievable additive manufacturing approach for all inorganic, titanium oxide metalenses that involves a variation of nanoimprint lithography using crystalline nanoparticle-based inks. By enabling direct “printing” of the lenses, the additive process stands. The proposed technology is in contrast to current multi-step subtractive fabrications of all-inorganic visible metalenses that are based on technologies and processes developed for the semiconductor industry. The team’s unique materials and process developments enable rapid cycle times, tunable refractive index (up to 2.1), and high aspect ratio features for highly efficient, all-inorganic flat lenses. State-of-the-art and innovative lens design and simulation are applied to take advantage of these unique and flexible fabrication capabilities and deliver outstanding lens performance, as confirmed by prototype testing. Key innovations in fabrication include developing stable nanoparticle inks, a unique pulsed UV light cure approach that provides intense but localized heating to rapidly stabilize the imprinted structures and remove organics without increasing bulk temperatures, and post-manufacturing treatments that further enhance the refractive index. While innovative, the process is scalable and will be demonstrated on full-scale manufacturing tools using commercially accepted solvents and process flows.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.