Conducting and semi-insulating crystals of GaAs grown by vertical Bridgeman (VB) and liquid encapsulated Czochralski (LEC) methods were studied by means of deep levels transient spectroscopy, photoinduced current transient spectroscopy, panchromatic microcathodoluminescence, optical absorption and electrical measurements. The most prominent traps observed in both types of crystals were the EL8, EL6, EL5, EL3 and EL2 electron traps. The results suggest that VB crystals are similar to LEC GaAs crystals grown from slightly Ga rich melts. The electrical properties and uniformity of VB crystals were greatly improved by the standard 950degreesC annealing procedure. (C) 2002 Elsevier Science Ltd. All rights reserved.