Study of dark current blocking layer for BiI/sub 3/ X-ray detector film

A blocking layer to decrease the dark current of BiI/sub 3/ X-ray detector was studied by depositing BiOI film on BiI/sub 3/ film. The quality of the BiI/sub 3/ film was evaluated by X-ray diffraction and photoluminescence. The carrier transport characteristics were evaluated by Hall measurement. The BiI/sub 3/ film was n-type and the BiOI film was p-type. The BiI/sub 3//BiOI film exhibited a rectifying current-voltage characteristics, indicating p-n junction formation between BiI/sub 3/ and BiOI films. The dark current decreased by two orders of magnitude in the reverse bias. The effective resistivity increased from 1/spl times/10/sup 9/ to 1/spl times/10/sup 11/ /spl Omega/cm using the blocking layer. The response time to X-ray pulse was less than 33 ms and the sensitivity value was considered to be promising. A BiI/sub 3/- BiOI junction band profile was estimated using the Hall measurement data.