Vapor growth of tetragonal prismatic mercuric iodide crystals

Tetragonal prismatic HgI₂ crystals are obtained from growth with low M_w polyethylene. Thermal desorption studies coupled with gas chromatography/mass spectroscopy (TDGC/MS) reveal the existence of normal alkanes and ketones in the growth ampoules with low molecular weight polyethylene. Polar bonds, such as carbonyl bonds found in ketones, may form weak bonds with Hg ions in the {220} faces, thus inhibiting the growth rate of the {220} faces. A tetragonal prismatic HgI₂ crystal grown with this method has been fabricated into a room-temperature Frisch collar γ-ray spectrometer with an energy resolution of 1.8% at 662 keV.