HgI/sub 2/ polycrystalline films for digital X-ray imagers

Abstract

This paper describes recent results obtained with mercuric iodide (HgI/sub 2/) polycrystalline films that we have produced. The ultimate goal of this effort is to develop a new detector technology for digital X-ray imaging based on HgI/sub 2/ polycrystalline films coupled to large-area flat-panel amorphous silicon thin-film transistor-addressed readout arrays. We have employed two approaches for producing the polycrystalline films: 1) thermal evaporation (sublimation) and 2) deposition of films from various solutions. The 50- to 150-/spl mu/m-thick films were characterized with respect to their electrical properties and in response to ionizing radiation. The leakage current was about 40 pA/cm/sup 2/ at an operating bias voltage of /spl sim/50 V. Signals from the HgI/sub 2/ polycrystalline detectors, in response to ionizing radiation, compare favorably to the best published results for all high Z polycrystalline films grown elsewhere, including TlBr, PbI/sub 2/, and HgI/sub 2/.