Junction Physics and Architectural Paradigms in Optoelectronic Semiconductor Fibers

Optoelectronic fibers are emerging as a foundational platform for distributed sensing, energy harvesting, optical communication in wearable electronics, soft robotics, and embodied intelligence. Unlike planar optoelectronic devices, fibers must intrinsically integrate light emission, detection, and modulation within scalable, deformable textile networks. In one-dimensional semiconductor fibers, device performance is ultimately constrained by junction formation under geometrically confined and dynamically evolving processing conditions, yet a unified framework for understanding and designing such systems remains lacking. Here, we establish a systematic junction centric framework that connects semiconductor physics, fiber-processing constraints, and device performance, thereby enabling coherent analysis and design across fiber solar cells, photodetectors, and light-emitting diodes. We then clarify how fiber-confined processing couples with microstructural evolution and junction formation, showing that the thermal, fluidic, and mechanical histories experienced during fabrication govern morphology and crystallization, thereby determining junction quality and device performance. These insights are further distilled into actionable strategies for realizing high fidelity in-fiber junctions. Finally, we highlight axially continuous and axially segmented junction configurations as key architectures for functional miniaturization and multifunctional integration beyond uniform fiber systems. Looking forward, major opportunities lie in integrating next-generation semiconductors into fibers, achieving high-fidelity junctions under continuous manufacturing, and realizing spatially addressable optoelectronic fibers for scalable system level integration.