Doping, a fundamental property of semiconductor devices can be measured at nanoscale thanks to long term developments made by IPVF-C2N researchers. In a twin papers published in Phys. Rev. Applied they report how to calibrate cathodeluminescence (CL) measurements to analyze p-type and n-type GaAs thin films over a wide range of carrier concentrations (2×10¹⁷ to 1×10¹⁹ cm^-3). Then, they applied this calibration to analyze the doping concentration profiles in GaAs NWs. High-resolution maps of the hole concentration demonstrate the homogeneous doping in the pure zincblende segment of the NW. For Si-doped GaAs NWs, the electron Fermi level and the full width at half maximum of low-temperature CL spectra are used to assess the electron concentration to approximately 3 × 10¹⁷ to 6 × 10¹⁷ cm^-3. These findings confirm the difficulty in obtaining highly doped n-type GaAs NWs, maybe due to doping compensation. The method developed in this work can be extended to other semiconductor materials.