A series of p-type GaAs layers grown by molecular beam epitaxy at temperatures below 600 degrees C directly on n⁺-type substrate was investigated by means of deep-level transient spectroscopy. The presence of nine hole-emitting traps was revealed, the Arrhenius plots of which are given. A comparison is made between layers not intentionally doped and layers isoelectronically doped with In. The trap suppression by In doping was found to be strong for most of the traps especially in layers grown at lower temperatures. The contribution of native defects and impurities to the observed trap spectra is discussed. Most of them were related to impurities, partly to transition metals. The so-called B level known as a native defect, was also found.