Hot ion implantation as a doping technique was used for the fabrication of visible‐light‐emitting diodes with GaAs1−xPx(x= 0.38 ± 0.01). Zinc ions,p‐type dopants, were implanted inton‐type (001)‐oriented heteroepitaxially grown Ga(AsP)‐on‐GaAs substrates at 400°C with an energy of 20 keV. Then, thermal treatment at various temperatures was carried out on the sample in order to investigate the effect of annealing on the electrical properties of Zn‐implanted layers in the Ga(AsP) substrate. Thep‐type layer, which was obtained by the ion implantation of 2 × 1015Zn ions/cm2with subsequent annealing at 900°C for 40 min, was found to have an effective surface concentration of 1.7 × 1015carriers/cm2and a sheet resistivity of about 100 &OHgr;/sq. Red‐light‐emitting Ga(AsP) diodes fabricated using Zn ion implantation have usually shown an average brightness of 400–600 fL, and sometimes as high as 850 fL at a current density of 10 A/cm2. Diodes, which were formed by means of a standard Zn diffusion technique in an evacuated ampoule at 750°C for 30 min using a ZnAs2source, had an average brightness of 350–500 fL at the same current density.