Texas State University - San Marcos

NSF Awards · FY 2024 · 2024-08

This project aims to serve the national interest by investigating conditions under which mathematics departments adopt and adapt evidence-based instructional materials for improving STEM education. To date, most research into dissemination of modeling curricula focuses on barriers and failures. This project plans to complement this work by studying successful adaptation processes at multiple sites and will produce an Evolution Blueprint. The Evolution Blueprint will summarize successful case studies and serve as a tailored resource to support faculty and institutions seeking to adopt the modeling curriculum. The focal instructional materials are from UCLA's Life Sciences 30 course, which teaches the importance of modeling feedback loops, positive and negative, in ecology, physiology, and molecular biology, all without a calculus prerequisite. The project seeks to examine the adaptability of these materials to new settings and deepen the field's understanding of how evidence-based curricular materials can be successfully disseminated. By understanding the conditions that facilitate successful dissemination off innovative curricular materials, future work can put them in place. In this way, the project contributes to improving the introductory mathematics experience for life science majors. The project will bring together mathematicians, mathematical biologists, and educational researchers to address a critical problem in STEM education related to the dissemination and uptake of evidence-based curricular materials and pedagogies. The project aims to achieve three goals: (i) identify and understand the contextual features that facilitate or impede successful implementation of a modeling-based curriculum, (ii) advance understanding of how ongoing, dynamic institutional conditions shape the adaptation of a modeling curriculum in response to local needs, and (iii) lay the groundwork for a multi-site impact study by developing assessment tools to measure broader learning outcomes. The project will draw on qualitative methodologies to document stakeholders' perceptions of the impact of the instructional materials, including the experiences of mathematics and science faculty, teaching assistants and tutors, and students. The project will develop local causal models that explain how and why aspects of the curricular materials are adapted to suit the instructional context. The NSF IUSE:EDU Program supports research and development projects to improve the effectiveness of STEM education for all students. Through the Engaged Student Learning track, the program supports the creation, exploration, and implementation of promising practices and tools. 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.

NSF Awards · FY 2024 · 2024-07

Studying the growth of emerging ultrawide bandgap (UWBG) materials and devices is crucial due to the growing demand for power electronic devices that can efficiently handle increased electrical power and operate at higher speeds without failure. These devices are the essential components in electric vehicles, power transmission lines that transport electricity from generation sites to households and industries, and electronic systems designed for high-temperature and radiation environments such as jet engines, nuclear reactors, and spacecrafts. Among UWBG materials, Gallium Oxide (Ga2O3) stands out as one of the most promising candidates for these applications due to its desirable electrical properties, good stability at high temperatures, radiation tolerance property, and abundance of electronic grade Ga2O3 wafers. Nevertheless, the limited thermal conductivity of Ga2O3 renders high-power devices fabricated from this material susceptible to failure. Growing diamond is another promising UWBG material with the highest thermal conductivity among all materials. As a heat dissipation layer on Ga2O3, it can address the poor thermal conductivity associated with Ga2O3-based devices. Since diamond can be easily doped p-type, integration with n-type Ga2O3 would lead to the fabrication of a p-n junction. However, the material quality of Ga2O3 drastically degrades in the harsh growth environment of diamond growth. This proposed work aims to address the ever-present challenges of growing delamination-free uniform and high-quality diamond film with a small thermal boundary resistance directly on UWBG oxides by incorporating an ultrathin quenched(Q)-carbon interlayer. Prototype p-diamond/n-Ga2O3 devices will be fabricated to assess their compatibility and determine the device characteristics. The outcomes of this project will contribute to the design of advanced and more compatible Ga2O3-based power devices. An important aspect of this study involves training both undergraduate and graduate students. Additionally, high school students will receive exposure to this research through summer workshop programs hosted at Texas State University. The project activities and outcomes will also be showcased through lab tours, demonstrations, visits to local schools, and on-site presentations, aiming to enhance scientific awareness among the public. Ultrawide bandgap (UWBG) Gallium Oxide (Ga2O3) based electronic device systems have the potential to handle extraordinarily large power across a wide range of frequency bands for next-generation high-temperature, high-power, and high-frequency applications. Two major bottlenecks to harnessing the true potential of this immensely promising UWBG material are the absence of p-type Ga2O3, which limits the fabrication of homojunction devices, and its low thermal conductivity, which directly impacts the device performance and reliability. In this regard, p-diamond/n-β-Ga2O3 integration offers potential solutions owing to diamond's superior thermal conductivity and p-type dopability. The diamond layer in the device can effectively dissipate heat during operation. However, lattice and thermal mismatch between Ga2O3 and diamond and issues related to harsh growth conditions for diamond are major challenges to implementing this concept. This proposal aims to address the persistent issues of integrating p-type diamond films with UWBG n-type Ga2O3 layer by implementing a novel approach, i.e., incorporating an ultra-thin quenched carbon (Q-carbon) interlayer achieved by pulsed laser annealing between the Ga2O3 and diamond interface. The Q-carbon layer on Ga2O3 will provide the nucleation base for high-quality uniform coverage diamond growth, protect the Ga2O3 layer from damage during the growth process, and reduce the thermal misfit between Ga2O3 and diamond. The project also aims to investigate the structural and electrical properties of each layer of the device and the heterointerface. Prototype Ga2O3-diamond p-n and p-i-n devices will be fabricated to measure the key performance parameters. 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.