We reports the development of a miniaturized optoelectronic component in which a gallium phosphide (GaP) nanowire (NW) serves simultaneously as an optical waveguide and an electrically-driven light source. By doping the GaP nanowire differently — either with Be (p-type) or Si (n-type) — we demonstrate integrated visible-range electroluminescence within a single nanostructure without needing separate emitter and waveguide elements. In the Be-doped GaP nanowires, regions with a direct wurtzite crystal phase act as nanoscale light-emitting sources, while the Si-doped wires guide light efficiently along their entire lengths. Using methods such as scanning tunneling microscopy, photoluminescence spectroscopy, and electron microscopy, we characterizes the structural and optical properties of these nanowires. The results show that such monolithically integrated light-emitting waveguides are promising building blocks for on-chip photonics and integrated photonic circuits, helping overcome challenges in coupling light emission with waveguides at nanoscale.
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