Electrically‐Driven Light Source Embedded in a GaP Nanowaveguide for Visible‐Range Photonics on Chip

Abstract The key components of photonic integrated circuits are nanoscale optica emitters and nanowaveguides. III‐V semiconductor nanostructures are considered as the most promising material platform for these components due to highly efficient luminescence and high refractive index, but the problem of emission coupling with waveguide is to be solved. In this work, the use of GaP nanowires (NWs) with different types of doping (GaP:Si or GaP:Be) is proposed as optical waveguides with directly integrated electrically‐driven light sources, solving the problem of emission‐to‐waveguide coupling. Single NWs are integrated with electrodes and pump electroluminescence by a tunnel junction allowing to study emission properties with nanoscale spatial resolution. Basing on the experiments on scanning tunnelling microscopy (STM), electron microscopy, time‐resolved photoluminescence micro‐spectroscopy, X‐ray diffraction, and STM‐induced electroluminescence, it is proven that GaP NWs exhibit different integrated light‐source on doping type of NWs. GaP:Be NWs contain inclusion of the crystalline wurtzite phase with a direct bandgap, and, thus, these NW regions can be considered as electrically‐driven nanoscale sources of light monolithically integrated into GaP NW‐based waveguides. Meanwhile, GaP:Si NWs work as optical waveguides capable of efficient light generation over the entire length of NW. The developed designs are promising for construction of integrated photonic circuits.