Previous work on photoacoustic spectroscopy (PAS) of semiconductors has been restricted to material in powder form. This letter shows that PAS can also be used to study intrinsic and extrinsic (impurity) absorption of semiconductors in bulk, single‐crystal form. For GaAs (Cr) the technique can easily detect Cr impurities at 5×1016cm−3level. The effects of surface preparation on the spectra are discussed.