PHOTOCURRENT MAPPING AS A PROBE OF TRANSPORT-PROPERTIES AND ELECTRIC-FIELD DISTRIBUTIONS IN CADMIUM ZINC TELLURIDE DETECTORS

We have performed two-dimensional cross-sectional photocurrent mapping of Cd0.9Zn0.1Te detectors grown by the high-pressure Bridgman method as a means of probing the electric field distribution, We have analyze d the results using a model based on the drift-diffusion equation, In the case of a uniform electric field and excitation far from the elect rodes, the result is virtually. identical in form to the Hecht relatio n, We adapt the Hecht relation to analyze photocurrent data and genera lize it to the case of a nonuniform electric field, The spatial distri bution of photocurrent for the material that we have examined suggests a nonuniformity. in either the electric field or the electron mobilit y-lifetime product, These observations may help to explain the slope c hanges observed in detector response pulses.