The Science and Technologies for Phosphorus Sustainability (STEPS) Center is a convergence research hub for addressing the fundamental challenges associated with phosphorus sustainability. The vision of STEPS is to develop new scientific and technological solutions to regulating, recovering and reusing phosphorus that can readily be adopted by society through fundamental research conducted by a broad, highly interdisciplinary team. Key outcomes include new atomic-level knowledge of phosphorus interactions with engineered and natural materials, new understanding of phosphorus mobility at industrial, farm, and landscape scales, and prioritization of best management practices and strategies drawn from diverse stakeholder perspectives. Ultimately, STEPS will provide new scientific understanding, enabling new technologies, and transformative improvements in phosphorus sustainability.

The RTNN is a consortium of three North Carolina (NC) institutions and is a site in the National Nanotechnology Coordinated Infrastructure (NNCI) network. NC State, Duke, and UNC-Chapel Hill are all located in close geographical proximity within North Carolina������������������s Research Triangle. The RTNN currently offers fabrication and characterization services and education to a diverse range of users from colleges, universities, industry, non-profits, and individuals. The RTNN brings specialized technical expertise and facilities to the National NNCI in areas that include wide bandgap semiconductors, soft materials (animal, vegetative, textile, polymer), functional nanomaterials, in situ nanomaterials characterization and environmental impact, nanofluidics, heterogeneous integration, photovoltaics, and positron annihilation spectroscopy. The RTNN strengthens the National NNCI in the areas of social and ethical implications of nanotechnology, environmental impacts of nanotechnology, and education/workforce development through interaction with industry and community colleges in the Research Triangle. All facilities engaged in this consortium have established track records of facilitating industrial research and technology transfer, strengths that further leverage the proposed site within the Research Triangle.

This project will seek to expand fundamental understanding of surface reactions during Atomic Layer Deposition (ALD) and Atomic Layer Etching (ALE) of novel complex dielectrics and related materials of interest to members of CDP. The work will build on and expand the successful collaboration1���5 in CDP between PIs Jones and Parsons who have been working together for the past ~3 years on ALD of HfxZr(1-x)O2

North Carolina State University will work with Sandia to characterize changes in microstructure and phase of the HZO as a function of radiation and cycling in order to elucidate origins of radiation-induced failure.

The overarching goal of this proposal is to determine the local effects of degradation throughout the thickness of piezo- and ferroelectric ceramics. This will be enabled using 3D analysis of the microstructure using advanced focused ion beam and tomography methods as well as Atomic Force Microscopy (AFM) techniques. The use of AFM has been successfully applied by co-PI Balke to reveal the local effects of bipolar fatigue in polished cross-section PZT ceramics [1]. In combination, this multi-modal approach covers many relevant length scales and will generate comprehensive insights into the mechanical and functional degradation throughout the thickness of bulk ceramics and will be applied to time and field-driven degradation relevant to actuator applications, such as aging and unipolar fatigue. This will allow to directly identify areas which are most affected by degradation, such as electrode-near regions, and identify their consequences on local and global piezoelectric and ferroelectric properties. Specifically, we will use (1) plasma Focused Ion Beam (pFIB) to rapidly characterize large blocks of fatigued regions both near the surface and in the bulk, (2) X-ray Nano-computed tomography (nano-CT) to identify the presence and location of internal microcracks, and (3) Piezoresponse Force Microscopy (PFM) to characterize the change in local domain structure, domain wall mobility, as well as qualitative changes in dielectric constant throughout the sample thickness. All local observables will be directly compared to macroscopically measured effects of degradation, such as strain and polarization to bridge the information obtained on different length scales and to explore the origin of degradation in the context of unifying degradation laws. This information will allow to establish the role of the microstructure and electrode/ceramic interface on reliability and lifetime predictions.

The Center for Dielectrics and Piezoelectrics (CDP) is an internationally recognized research center dedicated to improving the science and technology of dielectric and piezoelectric materials and their integration into components and devices. This class of materials underpins the functionality of a broad array of electronic and electromechanical systems that are enabling for the transportation, energy, aerospace and defense, communications, and medical sectors of the economy. In response to the needs and opportunities for academic-focused research to support these technology areas, the CDP was established in 2013 as a joint center between North Carolina State University (NCSU) and The Pennsylvania State University (PSU) and became an official NSF I/UCRC in 2014. The center attracts companies across the supply chain from raw materials suppliers, to component/subsystems manufacturers, to test equipment suppliers, to device and systems integrators.

This project objective is to advance our empirical understanding of how oxides and carbonates transform, decompose, and react at elevated temperatures and under various gas environments, enabling the design of new processing strategies for complex oxides. We will utilize in situ high-temperature X-ray diffraction (HTXRD) to systematically investigate many oxide and carbonate powders that are used as dopants in dielectrics and piezoelectrics, react them with other oxides and carbonates to understand their role in the formation of perovskites including K0.5Na0.5NbO3 (KNN), BaTiO3 (BT), and ternary perovskites such as BiFeO3-BaTiO3-SrTiO3 (BF-BT-ST), and develop the concept of using active, intermediate perovskite materials to form more chemically homogeneous perovskites that contain multiple cations.

The proposed research plans focus on pushing the boundaries of the synthesis of metastable perovskite oxides via new synthetic approaches. Metastable oxides, i.e., kinetically-trapped oxides with a positive free energy with respect to simpler oxides, can show superior properties, as found in many fields such as for photovoltaics, ion conductors, or multiferroics. Recent results demonstrate that access to ternary and quaternary perovskite oxides that are thermodynamically unstable can be achieved by using low temperatures and precursor oxides.

The research focus of the RET site is atomic-scale design and engineering. Participants in the program will be paired with research mentors in one of the three Research Triangle Nanotechnology Network (RTNN) institutions: NC State, Duke, or UNC. Research projects will enable participants to engineer, create, and characterize nanoscale materials or devices and connect their work to real-world applications. Teachers will gain experience with state-of-the-art tools and techniques that are used in scientific and engineering research. By integrating their research into creative lesson plans, educators can introduce nanotechnology concepts to their students, inspire and motivate them to pursue STEM careers, and prepare them for the scientific workforce. Participants will be recruited from local school districts (Johnston County Schools, Durham Public Schools) and community colleges with high populations of underrepresented students. Prior to conducting research, participants in the site will attend a week-long orientation. The following weeks will intertwine research activities with curricular development. To cap off the program, participants will finalize curricular materials and share their research experiences with fellow RET participants in a symposium. Upon return to their home institutions, educators will implement their curricula and work with open-access facilities at RTNN institutions to expose students to cutting-edge fabrication and characterization tools. Participants will share their curricula online as well as at local education conferences.

The objective of this project is to develop quantitative analytical methodologies for assessing the micro-scale qualities of biocement that give rise to macro-scale structural performance.