Photogalvanic effects in quantum wells

Circular and linear photogalvanic effects induced by far-infrared radiation have been investigated in both n-type and p-type quantum wells (QWs) of various point symmetry groups. The circular photogalvanic effect arises due to optical spin orientation of free carriers in QWs which results in a directed motion of free carriers in the plane of a QW perpendicular to the direction of light propagation. Due to selection rules the direction of the current is determined by the helicity of the light and can be reversed by switching the helicity from right to left.