Lynford Goddard, Ph.D. - US grants

Objective: The PI proposes using palladium and metal oxide nanoclusters as catalytic coatings for fast, high sensitivity/specificity, chemical to optical transduction. Coated, optically pumped, nanoscale VCSELs amplify and encode gas induced changes into an output power and/or wavelength shift for remote readout.

Intellectual Merit: This effort merges new research in nanoscale materials and device architectures to transform current scientific understanding of nanophotonic sensors. Gas induced lattice expansion of palladium nanoclusters is a hot research topic for electrical hydrogen sensors, but due to potential sparking, optical sensors are advantageous. The PI proposes expanding current research by characterizing the complex refractive index change caused by lattice expansion and testing sensors based on this effect.

Broader Impacts: Hydrogen is an attractive alternative fuel, but there is widespread public concern about its safe production and usage due to hydrogen's low flammability point of 4% in air. Poor response speed, sensitivity, and reliability of current hydrogen sensors could derail the future hydrogen fuel economy. Thus, this project can produce broad societal impact by demonstrating high performance sensors. Additionally, the research offers rich opportunities for teaching and training of graduate and undergraduate researchers in several disciplines. Participation of underrepresented groups will be broadened through on campus recruitment, REU internships, and K-12 outreach activities.

1040462
Popescu

This proposal is for instrument development of a spatial light interference microscopy facility that will measure samples in both transmission and reflection modes. This quantitative phase imaging instrument will benefit diverse research efforts in the materials and life sciences. In particular, it will enable: (1) non-destructive inspection of nanostructures, semiconductor devices, and new materials such as graphene and carbon/semiconductor nanotubes, (2) observation of the dynamics of live cells and transport in neurons, and (3) exploration of new cancer detection techniques. Current topographic imaging technology severely constrains the size and sheer number of samples that can be measured at high resolution. Thus, the information gathered and new understanding obtained is thereby limited. Numerous new lines of research and opportunities for discovery in fields ranging from medicine and life sciences to semiconductors and material sciences will be enabled once this new form of fast microscopy is made accessible. Further, development of this transformative scientific instrument will provide rich opportunities to broadly integrate research and education.

Objective: The objectives of this program are to characterize, model, and utilize reflective microring reflectors. The PI proposes engineering novel device functionality by integrating a Bragg reflector in a microring resonator. The microring amplifies grating reflection, creating a compact mirror with high reflectivity, narrow linewidth, and no side lobe ripple. These benefits would reduce channel crosstalk and potentially result in lower power, higher data rate communication systems.

Intellectual Merit: The intellectual merit is that the research will advance scientific understanding of the device and demonstrate its potential as a fundamental element to the photonics community. The PI proposes to leverage his preliminary results in device theory, experience in lasers, sensors, and nanofabrication, and experimental capabilities and resources. The research is potentially transformative as it may unlock new lines of research (new devices and models) and enable diverse applications (interferometry, metrology, RF photonics, and communications). Two specific applications will be explored: as cavities for on-chip absorption spectroscopy and as mirrors for tunable lasers.

Broader Impact: The broader impacts will be to create novel devices for next generation communications and consumer electronics. Research and teaching will be integrated through the development of two courses: Principles of Experimental Research? and Modeling of Photonic Devices. Recruitment, retention, and participation of students from underrepresented groups will be addressed through mentoring, REU internships, and a new electrical engineering summer camp for 10th-12th grade girls. Results from both research and teaching will be published to enhance the current understanding of reflective microring devices and engineering education/outreach methodologies.

This award provides funding for a three year standard award to support a Research Experiences for Teachers (RET) in Engineering and Computer Science Site program at the University of Illinois Urbana-Champaign (UIUC) entitled, "nano@Illinois RET: Reseaerch Experience for Teachers Site in Nanotechnology", under the direction of Dr. Xiuling Li.

UIUC proposes to develop and deliver the exciting nano@Illinois RET program, which will expose a total of 42 (14 per year) in-service and pre-service STEM teachers and community college faculty from across the nation to cutting-edge research in nanotechnology over six weeks in the summer, with four follow-up sessions during the school year. Specifically participants will be mentored and trained in broad areas of nanotechnology, while delving deeper into their chosen area of interest, including nanoelectronics, nanophotonics, nanomanufacturing, nanomaterials, or nanobiotechnology. These participants will connect their research experiences to their content areas, including physics, chemistry, biology, math, and engineering. The specific projects are motivated by grand challenges facing our society and the world in informnation technology/communications, energy, security, health, agriculture, and environment. More specifc topic areas range from scaling of current electronic devices; creating new electronic or photonic nano-devices; reducing the cost of sequencing the human genome; point of care detection of pathogens and diseases; to creating highly pervasive energy harvesting ecosystems.

The Site will leverage institutional knowledge and educational resources developed through the NSF Center for Nanoscale Chemical-Electrical-Mechanical-Manufacturing Systems (Nano-CEMMS). This Site will bring a diverse group of teachers together from three local school districts in an environment serving the University's research, teaching, and learning goals. Participants will benefit from continuous engagement with exceptional faculty and students; access to unparalleled laboratories and equpment; and well-organized, executed, and managed program components. The Site will provide an in-depth experience for teachers and extend the teacher network established through Nano-CEMMS, from elementary, middle, and high schools to community colleges.

Abstract:
Non-Technical: Semiconductor devices are ubiquitous. They represent a multi-trillion dollar industry. Ordinary objects such as electrical outlets, thermostats, and blood pressure/heart rate monitors, are being embedded with increasingly complex control electronics, sensors, and network connectivity to enable greater functionality, value, and service. Although foundry services exist for large volume manufacturing of microelectronics for ?smart? objects, there are no cheap (<$100/run) rapid turnaround (<1hr) options for garage inventors to prototype new ideas. The biggest hurdles are that conventional microfabrication requires a cleanroom and expensive (>$1M) equipment. This NSF project seeks to democratize semiconductor manufacturing by investigating a new fabrication paradigm in which pulses of light of specific colors catalyze electrochemical reactions that dope, etch, and metallize designated circuit patterns onto a semiconductor wafer with high resolution. The project offers rich opportunities for high school and community college teachers to participate in research and develop teaching modules for hands-on labs through Research Experiences for Teachers projects. Research and teaching will be integrated through the PI?s ?Principles of Experimental Research? course. Graduate and undergraduate students will be trained in semiconductor micro- and nano-fabrication, photonics, optical system design, fluid mechanics, and bio-sensors through the proposed research activities. Recruitment, retention, and participation of students from underrepresented groups will be addressed through Research Experiences for Undergraduates internships and engineering summer camps for 9th-12th grade girls. Results from both research and teaching will be widely disseminated in journals and conferences to enhance the current understanding of photoelectrochemical processing and of engineering education/outreach methodologies.
Technical: Photochemical etching uses light to generate minority carriers that catalyze semiconductor wet etching. Recently, the PI?s team implemented photochemical etching using a projector. The local etch rate was controlled using color images drawn in PowerPointTM. Here, the team seeks to drastically improve the etch resolution and anisotropy and expand the method to enable new types of light controlled processes, e.g. patterned doping and metallization, so that new classes of unconventional photonic devices and multifunctional integrated circuits can be fabricated in a single system. In the proposed system, a super-continuum laser, tunable filter, and spatial light modulator will generate high intensity spectrally engineered dynamic image pulses and a synchronized electrical pulse generator will temporally gate the chemical reactions. If successful, this project is potentially transformative because it could create a new semiconductor fabrication paradigm for several reasons. First, multiple processing steps, e.g. doping, etching, and metallization can be performed sequentially in the same system. Second, these processes can be easily aligned to features made through conventional cleanroom processing since the illumination pattern can be adjusted in software. Moreover, this dynamic illumination capability enables new designs to be rapidly prototyped. Next, the processing rate for different bandgap materials can be individually adjusted. Finally, the limitations imposed by conventional planar fabrication technology can be removed and complex 3D devices can be fabricated with precisely controlled dimensions. The overall research goals of this project are to:
1. Understand how spectral and temporal gating affects the resolution, anisotropy, photo-induced selectivity (e.g. light on vs. off), and material selectivity (e.g. GaAs vs. AlGaAs) of the etch;
2. Develop photo-induced electroplating and doping techniques; and
3. Fabricate unconventional devices with complex topography.

Low-income students are underrepresented in engineering and more likely to struggle in engineering programs. Research has found that increasing first and second-year retention enhances the ability of academically talented low-income students to successfully graduate with engineering degrees. In this collaborative research project six institutions will replicate, improve, and test a model of student success originally developed at the University of Colorado, Boulder. The model is designed to increase the retention, success, and graduation of low-income (Pell-eligible) academically talented students from underserved populations. The project will make scholarship awards to 800 students across a consortium of the six partner institutions. To support the students, the project will adapt and implement an ecosystem of high quality evidence-based curricular and co-curricular activities. Members of the consortium are: the University of Colorado, Boulder; the University of Washington; Washington State University; Boise State University; the University of Illinois, Urbana-Champaign; and the University of California, San Diego.

The Redshirt in Engineering Consortium is committed to propagating the "Redshirt" model, which focuses primarily on the first-year of college and consists of intrusive academic advising, an innovative first-year academic curriculum, community building, and career awareness. The term "redshirt" refers to the idea of providing an extra year of preparation for the rigors of engineering curricula. A quantitative and qualitative mixed methods research study will examine the implementation of the model under different conditions and with different student populations. A comparative longitudinal study will examine differences in expected student outcomes between scholarship recipients and similar students who are pursuing engineering degrees. The primary analytic approach for the ethnographic research will be the Constant Comparative Analysis, which will involve concurrent engagement in data collection and data analysis.

Despite the prevalent use of light to carry information in modern computer networks, data centers, and telecommunications systems to support society's ever-increasing demand for bandwidth, limited progress has been made on the use of light to carry information between or on integrated circuit chips. Even less progress has been made on circuits that use light to process information. A key impediment to progress on true electronic-photonic integration has been the lack of a circuit element that operates in both the domain of light (photons) and electrons. An important breakthrough, made at the University of Illinois in Urbana-Champaign by Professors Nick Holonyak, Jr. and Milton Feng, is that certain types of transistors (the basic building blocks of electronic circuits) can be modified to generate and be acted on by light. These light-emitting transistors (LETs) and transistor lasers (TLs) will be used in this program to form true electronic-photonic digital logic circuits, and high-speed optical links both on and between chips. This technology is expected to dramatically improve the speed and energy efficiency of devices that process information, and to enable the commercial success of a new class of integrated circuits at the forefront of performance. Education and outreach activities will introduce undergraduates and high school teachers to a new technology based on light, renewing excitement in STEM-related fields and the creating the promise for a future career in electronic-photonic circuit engineering.

The technical work in this program is focused on bringing into existence a basic electronic-photonic circuit that can be used as the core building block for ultra-energy-efficient electronic-photonic computing systems. A multidisciplinary team has been assembled with expertise that spans the areas of semiconductor physics, materials and device processing, device design, high-speed circuits, and computer architecture to attack a variety of technical challenges and create a viable technology platform. At the fundamental level, physics-based models will be developed for the devices to optimize them for electronic and photonic functionality and predict their performance in an electronic-photonic circuit. In tandem, devices and circuits will be fabricated and characterized to optimize their performance and to improve the device models. Incorporating these devices and circuits into systems with conventional silicon circuits will require the development of scalable processing technologies that allow the formation of electronic-photonic "islands" embedded within silicon chips along with the electronic and photonic interconnects within and between these islands. Finally, architectures will be developed at the chip and system level that make optimal use of the functionality provided by these electronic-photonic logic circuits.

The fundamental goal of this research project is to develop a route to form high performance photonic devices within the volume of a silicon wafer rather than on its surface, as is generally the case. Photonic devices are integral to many important applications in telecommunications, computing, data storage and transfer, and consumer electronics. Silicon photonics has enabled circuits that are miniaturized and integrated. These technologies will dramatically improve in speed, density, and energy efficiency if they can be successfully integrated at a high enough density as a multi-plane photonic integrated circuit (PIC). Two key projected societal impacts are (1) ultra-high speed data transfer within next generation computers using channels that route light in 3D within a chip or between chips and (2) advanced all-optical signal processing using a PIC that has numerous planes for performing operations. The project also includes the training of undergraduate and graduate researchers in photonic device/circuit theory, microfabrication, metrology, and numerical simulation. Research and teaching will be closely integrated through three of the PI's courses: Materials in Nanotechnology, Integrated Optoelectronics, and Principles of Experimental Research. Participation of students from underrepresented groups will be broadened through undergrad research and by leveraging large existing K-12 outreach initiatives that will impact greater than a thousand students.
The PIs propose a proof-of-concept project to realize multiple planes of interconnected micro-optic elements, waveguides, and passive photonic devices within the volume of a silicon wafer. Subsurface gradient refractive index (GRIN) devices will be fabricated within porous silicon (PSi) or silica (PSiO2 = oxidized PSi) via two-photon lithography to selectively polymerize photoresist within the porous host. This direct laser writing (DLW) approach enables index control (nPSi = 1.4-1.9, nPSiO2 = 1.15-1.3) at each voxel. Complex GRIN elements (e.g., compound apochromatic lenses, photonic nanojet emitters, diffractive and photonic bandgap structures, spiral phase plates, and index/mode matching bamboo-shaped tapers) plus conventional silicon photonic elements (e.g., interferometers, gratings, and microring multiplexers and filters) can all be fabricated in a self-aligned manner with < 1 micron critical dimensions across a 4" wafer. The research seeks to advance knowledge in the fields of subsurface fabrication and photonic integration. The interdisciplinary team of 2 PIs, 2 grad students, and 2 undergrad students will leverage their experience and training in GRIN PSi and PSiO2 optics, DLW, optical device/circuit theory and design, computational electromagnetics, imaging, metrology, and nanomanufacturing to answer fundamental scientific questions about the fabrication of complex optics by addressing five major goals:
1. Investigate and apply polymerization-based index control and optical characteristics in mesoporous scaffold-enabled two-photon lithography.
2. Measure the spectral dependence of the refractive index and absorption coefficient (400 - 1700 nm) as well as the 3D point spread function of the writing process.
3. Develop software tools to: (a) optimize the 3D index profile to achieve a given optical functionality and (b) determine the necessary two-photon lithography exposure conditions to realize said profile.
4. Design, fabricate, characterize, and model novel GRIN elements and subsurface 3D waveguides.
5. Demonstrate the aforementioned monolithically integrated 8-plane PIC and optical interposer.
Demonstration of previously unachievable photonic geometries and functionalities will not only create a new paradigm for future PIC architectures but will also lead to new scientific applications such as lab-in-chip, interferometry, metrology, imaging, and quantum optics.

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.