Piezoelectric effect and the long-term resistance relaxations induced by uniaxial compression in p-GaAs/AlxGa1−x as heterostructures

Long-term resistance relaxations induced by uniaxial compression in (001)p-GaAs/Al0.5Ga0.5 As heterostructures are observed, and the main properties of these relaxations are investigated: the dependence of their character on the direction of the uniaxial compression, the change in concentration of current carriers during the relaxation processes, and the quenching of the relaxations by temperature, illumination, and high electric fields. It is found that the character of the relaxation process is different for compression directions [110] and \([1\bar 10]\): in the first case the concentration of two-dimensional holes in the quantum well decreases in the course of the relaxation, while in the second case it increases. A model is proposed in which the cause of the relaxations of the piezoresistance and the anisotropic character of these relaxations is assumed to be the piezoelectric field, the value of which, according to estimates, is |Ez| = 1.152 × 104 V/cm per kbar.