Two MSE PhD students receive 2021 NSF Fellowships

John Kim and Ahmad Matar Abed received the prestigious award for their outstanding research in the areas of conjugated polymers and ultra-wide bandgap semiconductors, respectively.
Two MSE PhD students receive 2021 NSF Fellowships

Ph.D. candidates John Kim (Lahann) and Ahmad Matar Abed (Peterson)

MSE is proud to announce that two of our Ph.D. students, John Kim and Ahmad Matar Abed, were recently granted NSF fellowships for the 2021-2022 year.

The purpose of the NSF Graduate Research Fellowship Program (GRFP) is to "help ensure the vitality and diversity of the scientific and engineering workforce of the United States. The program recognizes and supports outstanding graduate students who are pursuing full-time research-based master's and doctoral degrees in science, technology, engineering, and mathematics (STEM) or in STEM education."

The GRFP provides three years of support for the graduate education of individuals who have demonstrated their potential for significant research achievements in STEM or STEM education.

As a member of the Lahann group, Kim won the NSF Fellowship for his proposal "Investigation of optoelectronic and fluorescent properties of tunable arrays of poly-(p-phenylene vinylene) nanofibers." A summary of his research follows: 

Conjugated polymers are of modern interest due to a unique set of optical and electronic behaviors. One class of conjugated polymers are those based on poly-(p-phenylene vinylene) (PPV). PPV are known to exhibit semiconducting property, electroluminescent, photoluminescent, and photovoltaic responses. PPV has been utilized to synthesize one-dimensional structures, mainly nanofibers, for applications in photovoltaic devices, optical sensors, and linearly polarized fluorescent materials. The most commonly used process in the fabrication of PPV nanofibers is electrospinning, as it allows for dimensional (e.g., length, density, and diameter) and morphological (e.g., straight, twist, and bent structures) tuning of PPV nanofibers. To advance the investigation of PPV nanomaterials, more delicate control over orientation of end-attached arrays of nanofibers would be desirable. A considerable amount of research on inorganic nanofibers with such structure has been conducted for applications such as artificial tactile sensors (electronic skin; aligned graphene nanofibers) and optical sensors (optoelectronic gating materials). In these cases, adjustments to processing conditions offer options for orientational, dimensional, and morphological tuning simultaneously. This, in turn, allows detailed structure-function studies related to device performance. Unfortunately, the current methods for polymeric nanofibers offer limited access to a large degree of control over the uniform orientation of the end-attached nanofibers. In a recent work from Professor Joerg Lahann’s group, arrays of polymer nanofibers were realized via chemical vapor polymerization (CVP) on surfaces templated by an appropriately selected liquid crystalline (LC) phase. This system has resulted in various structures of nanofibers such as helical, bent, vertical, and three-dimensional network structures of nanofibers. In this proposal, optoelectronic properties of PPV nanofibers with different morphological factors (density, height, and diameter) will be investigated. Furthermore, it is expected that adding a chiral-center to a dichloro p-xylylene precursor will allow for chiral nanofibers that exhibit circularly polarzied fluorescence.

Abed, with the Peterson group, received the award for his proposal, "Growth, doping, and charge transport mechanism of novel Ge-based oxide semiconductors.” A summary of his research is below:

Ultra-wide-bandgap (UWBG) semiconductors have attracted great attention due to their extraordinary properties for potential applications in high-power electronics, quantum information, and extreme-environment applications. UWBG materials have bandgaps larger than traditional semiconductors, enabling a larger breakdown strength that leads to increased power density and reduced energy loss in power devices. Currently, UWBG materials such as beta-phase gallium oxide are being intensively researched due to their large breakdown field and Baliga Figure of Merit (BFOM), which predicts the performance of a material in power-electronic devices. However, this material can only be n-type doped and has low thermal conductivity, inhibiting efficient heat management in future power applications. Recently, it has been reported that rutile germanium dioxide has ambipolar doping capability, and both higher thermal conductivity and predicted BFOM when compared to beta-phase gallium oxide. I propose exploring the unique superior properties predicted by the theory of Ge-based oxides, such as rutile germanium dioxide, to experimentally confirm their capabilities. UWBG semiconductors will enable the next generation of high-voltage and high-power electronics by providing critical technologies for a more sustainable and equitable future, which includes grid integration of renewable energy sources and energy-efficient transportation.

Congratulations to both John and Ahmad!