Textured α-HgI2 ceramics for sensitive X-ray detection

In the prospect of manufacturing ionizing radiation detectors, dense ceramics of α-HgI2 with a strong preferred orientation were elaborated. X-ray diffraction showed that most crystallites exhibited their crystal c-axis perpendicular to the ceramic plane, which should be favorable for optimum electrical transport properties. Dark current densities about 2 nA mm−2 (under 0.2 V μm−1 bias) were measured and were shown to arise mostly from the release of carriers from trap defects (Poole-Frenkel emission). The X-ray sensitivity ≈1600 nC mGy−1 cm−2 and the μτ value ≈3×10−5 cm2 V−1 were comparable to those of other forms of polycrystalline HgI2. The HgI2 ceramics also exhibited a perfectly linear response as a function of the X-ray dose.