A nanostructured pn junction light-emitting diode is fabricated from a semi-conducting substrate doped by a first dopant and covered by a dielectric thin layer. An amorphous thin film formed by a semi-conducting material doped by a second dopant of opposite type to that of the first dopant is then deposited on the surface of the dielectric thin layer. The assembly then undergoes a thermal treatment designed to form, in the dielectric thin layer and from the amorphous thin film, a plurality of dots of nanometric size and made of semi-conducting material doped by the second dopant. The dots are designed to be in epitaxial relationship with the substrate to form a plurality of pn junctions of nanometric size. An additional thin layer is then formed by epitaxial growth from the dots.