Characterization of metal contacts on and surfaces of cadmium zinc telluride

In the past several years significant progress has been made in building a database of physical properties for detector quality CdxZn1-xTe (CZT) (x = 0.1-0.2) crystal material. CZT's high efficiency combined with its room tem perature operation make the material an excellent choice for imaging and sp ectroscopy in the 10-200 keV energy range. For detector grade material, sup erior crystallinity and high bulk resistivity are required. The surface pre paration during the detector fabrication plays a vital role in determining the contact characteristics and the surface leakage current, which are ofte n the dominant factors influencing its performance. This paper presents a s urface and contact characterization study aimed at establishing the effects of the surface preparation steps prior to contacting (polishing and chemic al etching), the choice of the metal and contact deposition technique; and the surface oxidation process. A photoconductivity mapping technique is use d for studying the effects of different surface treatments on the surface r ecombination. (C) 1999 Elsevier Science B.V. All rights reserved.