DX CENTERS IN CDZNTE-CL AND THEIR APPLICATIONS

DX centres, far from being undesirable defects, can be very useful: th e persistent photoconductivity (PPC) associated with them makes it pos sible to optically write erasable metallic patterns in an insulating b ackground; potential applications include optical switching and hologr aphy. In order to develop room-temperature devices, we study II-VI sem iconductors in search of DX centres which can support PPC to 300 K. Me asurements of the PC and Hall effect in Cl-doped Cd1-xZnxTe show that Cl donors form two distinct DX states. Only one is apparent for x = 0. 20, but for x = 0.28 the transport measurements evince an additional D X-like state into which the photocarriers are metastably captured. In the latter, the PPC persists to 190 K.