Characterization of Screen-Printed Mercuric Iodide Photoconductors for Mammography

Abstract

We describe energy-dependent incomplete signal generation in semiconductor detectors with a simple planar geometry using deep charge trapping and depth-of-interaction models. Based on this formalism, we have characterized mercuric iodide (HgI2) photoconductors by extracting performance parameters from x-ray-induced signals under mammographic imaging conditions. The HgI2, sample photoconductors were prepared using a simple screen-printing method. For an x-ray tube output from tungsten target and 30-kV setting, the quantum absorption efficiency of samples with a thickness of approximately 0.1 mm was measured to be similar to 70%. X-ray sensitivity was measured to be 0.4 nC cm(-2)mR(-1). Mobility-lifetime products for electrons and holes were measured as similar to 2 x 10-6 cm(2) V-1 and similar to 0.9 x 10-6 cm(2) V-1, respectively. Considering incomplete charge collection, the W-value (or w) was estimated to be rsd similar to 27 eV. Since the characterization method described in this study is simple and does not require sophisticated equipment, it can be useful for the characterization of photoconductor materials.