Transmission electron microscopy of semi-insulating Ga As deformed at room temperature and under confining pressure

GaAs single crystals have been deformed by compression at room temperature under a confining pressure of 600 MPa. Two competitive mechanisms of plastic deformation are proposed. The first mechanism is supported by the observation of mobile perfect (or slightly dissociated) α dislocations. The second mechanism involves less mobile widely dissociated β (or screw) dislocations. It is suggested that the large dissociation of these dislocations is due to the lower mobility of the 30° (β) partials Deformation d'echantillons GaAs a temperature ambiante et sous une pression de confinement de 600 MPa et proposition de deux mecanismes de deformation plastique. Le premier s'appuie sur l'observation de dislocations α parfaites ou peu dissociees tres mobiles. Le second fait intervenir des dislocations β (ou vis) largement dissociees et moins mobiles. La dissociation de ces dissociations pourrait etre due a une mobilite plus faible des dislocations partielles 30° (β)