The scintillating layer coupled to amorphous silicon photodiode with thin routing electronics have a good prospect as a substitute of conventional X-ray film. There is a need to fabricate the CsI(Na) with high light output. In this study, thin film was fabricated with optimum thickness, depending on many process parameters, then, the light output was investigated as a function of defect concentration. Finally, relation between three kinds of defects which emits light was discussed.
In chapter IV-1, thin, homogeneous CsI(Na) scintillation layers (area as a large as 30㎠)have been produced by vacuum evaporation of the mixture of CsI and NaI powder, and growth mechanism of thin film was discussed, with various evaporating conditions. With outstanding, columnar structure and. As deposition rate increased, the columnar diameter become smaller, and vice versa. Finally, general poly crystalline structure was developed. X-ray data showed that the strong dependency of crystal orientation was developed, as deposition rate increased. And the effect of post heat treatment was investigated. As annealing temperature increased, grains become growing.
In chapter IV-2, the effect of defect concentration to light output was discussed. To control the defect concentration, annealing with various temperature was accomplished, evaporation was accomplished with various doping level. Successive annealing have had a decisive role for discriminate the different color centers.
It was revealed that there was two kinds of color center - intrinsic color center, and extrinsic color center. And depending on doping level, annealing temperature, and room temperature aging, the dominant color center was changed. Besides, there was competition relation between two sorts of color centers.
