APPLICATION OF EDDY-CURRENT TECHNIQUE TO VERTICAL BRIDGMAN GROWTH OF CDZNTE

The eddy current technique was used to reveal the interface shape duri ng vertical Bridgman growth of CdZnTe and to follow changes in the pro perties of the solidified ingot as it was cooled to room temperature a fter growth. Experiments were performed where partially solidified cha rges were decanted to show the interface shape. Eddy current analysis of the partially solidified charge indicated a concave interface shape in qualitative agreement with the shape of the decanted ingot. Howeve r, due to noise, interference, and possibly the inhomogeneous nature o f the melt, only some of the eddy current signals could be analyzed em pirically for interface shape; absolute values of conductivity could n ot be calculated from the eddy current data. Eddy current measurements made to follow changes in conductivity during post-growth cooling sho wed a minimum in the data during an 800 degrees C annealing step indic ative of a transition in the electrical properties of the ingot. On fu rther cooling, a dramatic increase in the bulk conductivity of the ing ot was noted. Such a transition can probably be described as a Mott tr ansition.