In this paper, we measured the experimental amplitude and phase of the Photothermal deflection signal for bulk GaAs “silicon” doped n + type, “chromium” doped n type and “carbon” doped p type in order to determine the nonradiative recombination parameters. The results obtained for non-radiative lifetime and the electronic diffusion agree with those appearing in the literature for similar samples. By comparison with values reported in literature, the increase of doping density favors auger recombination that produce an increase of non-radiative lifetime. We have found that electron mobility in p type C-doped GaAs is about 300 cm2/V·s. In fact, holes motilities are respectively 177 and 193 cm2/V·s for n + type Si-doped GaAs and n type Cr-GaAs doped. However, we obtained high values of the recombination velocity for non passivated surface.