Greensboro, N.C. — At the Joint School of Nanoscience and Nanoengineering (JSNN), Prof. Shanthi Iyer is advancing a research program that sits at the intersection of epitaxial crystal growth, nanoscale materials, and optoelectronic device engineering. Her group’s central goal: use molecular beam epitaxy (MBE) to grow and tailor GaAsSb(N) nanowires that can become high-performance infrared (IR) photodetectors—including device concepts that integrate directly onto silicon and graphene platforms. Why nanowires—and why infrared? Infrared detection underpins technologies ranging from optical communications to sensing and imaging. Nanowires add an extra advantage: their geometry and heterostructures can be engineered to tune optical response while relaxing some constraints that typically make integrating III–V semiconductors on other substrates challenging. At JSNN, Prof. Iyer’s research explicitly targets MBE growth, characterization, and device fabrication of GaAsSb(N) nanowire-based IR photodetectors, with an emphasis on epitaxial integration into Si and graphene for “next-generation photonic devices,” according to JSNN’s faculty profile. jsnn.ncat.uncg.edu Recent research outputs: graphene integration and near-IR device performance In recent years, the Iyer Lab has reported multiple device-facing nanowire architectures aimed at near-infrared response: A 2024 publication listed by JSNN highlights “High-responsivity N-I-P axial/core-shell GaAsSb dense nanowires” and describes a novel integration with a graphene substrate for near-infrared photodetectors. jsnn.ncat.uncg.edu A 2023 publication highlights “a GaAs/GaAsSb core-shell configured nanowire-based avalanche photodiode” with detection “up to 1.3 µm,” aligning with key near-IR wavelength regimes used in photonics. jsnn.ncat.uncg.edu Together, these works reflect a consistent theme: nanowire heterostructure design (axial + core/shell) paired with substrate strategies (including graphene) to push toward practical IR detection platforms. jsnn.ncat.uncg.edu The growth challenge: controlling Sb incorporation A major scientific hurdle in GaAsSb nanowires is controlling antimony (Sb) incorporation, which strongly influences band structure and optical properties. Earlier work in Scientific Reports (2017) describes a “two-step growth pathway” enabling high Sb incorporation in GaAsSb nanowires targeting telecommunication-relevant wavelengths—illustrating how growth-process design can unlock new composition regimes. Nature From lab methods to protected IP JSNN news and faculty highlights also point to translation-oriented progress through patents: US Patent 11,384,286 (issued July 12, 2022): “GaAs₁₋ₓSbₓ Nanowires on a Graphitic Substrate,” credited to work at JSNN by Iyer, Surya Nalamati, and Jia Li, describing approaches for nanowire growth and applications. US Patent 11,905,622 (issued Feb. 20, 2024): “High Sb Concentration GaAsSb/GaAs(1-x)SbxN/GaAlAs Core-Shell-Shell Nanowires,” listed in JSNN’s profile and mirrored in public patent listings. A related patent dated Feb. 11, 2025 is also listed publicly as a granted item tied to the same “high Sb concentration” nanowire family and inventors. Justia Patents Funding and impact: DoD-aligned photonics needs JSNN’s 2022 faculty achievement highlights report that Prof. Iyer received: An Air Force Research Laboratory grant on nanowire-based avalanche and high-speed photodiodes for advanced LADAR, and An Army Research Office grant on dilute nitride GaAsSbN nanowire-based high-speed near-infrared photodetectors. JSNN’s profile further notes Prof. Iyer’s role in initiating and developing NC A&T’s MBE Laboratory and states she has served as PI on over $10M in DoD research projects, underscoring both infrastructure-building and sustained program-scale research activity. The JSNN advantage: shared infrastructure and regional access This work is amplified by JSNN’s broader ecosystem. JSNN emphasizes partnerships across academia, industry, and government and is part of the National Nanotechnology Coordinated Infrastructure (NNCI). It also helped establish the Southeastern Nanotechnology Infrastructure Corridor (SENIC) with Georgia Tech—an open-access approach designed to broaden access to advanced fabrication and characterization tools. As photonics and sensing demands continue to move toward faster, smaller, and more integrable devices, the Iyer Lab’s approach—MBE precision growth + nanowire heterostructures + integration onto Si/graphene—positions JSNN to contribute both fundamental advances and device-ready pathways. With a track record spanning high-Sb growth strategies, near-IR detector concepts, patents, and defense-relevant funding, Prof. Iyer’s program highlights how nanoscale materials engineering can translate into real photonic technologies.