To study the effect of damage induced during the Zn diffusion on the properties of the material, p-n junctions, obtained by zinc diffusion, are investigated by electron beam induced current (EBIC) at different temperatures. At helium temperature, the EBIC decay on the p-side is flattened and non exponential. This effect is attributed to the defects induced by the Zn-diffusion that act as non-radiative centers. The room temperature EBIC signal has a symmetric exponential decay on both sides of the junction. The EBIC measurements for different temperatures and electron beam voltages indicate that the surface recombinations affect the carrier transport at room temperature hindering the non-exponential EBIC decay observed at helium temperature. The recombination dynamic is affected stronger by the as grown (001) surface than by the cleaved (110) surface.