A systematic study of mercuric iodide platelet growth in horizontal furnaces

Abstract

Growth of mercuric iodide platelets in horizontal furnaces with the addition of polyethylene powder has been analyzed with a 2 3 full factorial analysis. The factors investigated were the temperature gradient between the zones, the source/hot zone temperature, and the amount of polyethylene powder. The crystallization zone length was chosen as the observable. Normal probability and Lenth's plots were used to analyze the effects. Both plots show that the temperature gradient is an active effect.

Vapor Growth of Mercuric Iodide Tetragonal Prismatic Crystals

“…The effects of the stoichiometry and purity of the starting HgI 2 were deemed inconsequential, unlike claimed previously in [29,30] Gases -Therefore, the organic materials seemed to behave as inert gases, prompting futher studies in HgI 2 mass transport in horizontal furnaces [48][49][50][51], as well as HgI 2 with inert gases [52,53] Faile -Purification of the starting HgI 2 was not done because the author believed that HgI 2 purification was not needed to produce platelet crystals. Although the formation of HgI 2 platelet was not known, and was not attempted to be proven, the author assumed that polymer transport, formation, and/or disassociation might be the factors that influenced the platelet formation.…”

“…The analysis of the results implies that instead of having the characteristics of a chemical vapor transport, as claimed in [29], the analyzed vapor transport has the characteristics of a physical vapor transport, with sublimation and condensation of HgI 2 being the principal crystallization processes [32]. Therefore, the organic materials seemed to behave as inert gases, prompting futher studies in HgI 2 mass transport in horizontal furnaces [48][49][50][51], as well as HgI 2 with inert gases [52,53] The presence of residual gases mentioned above and the total pressure inside the ampoule are partially responsible for the shapes of the crystals. The existence of convective flow (causing non-stable growth forms) was implied by the occurrence of needleand dendrite-shaped crystals, while a more stable growth would produce crystallites and platelets.…”

“…Technologies (SMART) Laboratory at Kansas State University was started based on the prevalent understanding that vapor transport, with factors such as temperature profiles and starting material amounts, had the biggest influence on the growth [53]. For one type of additives, the amount of starting materials and the total pressure in the ampoule did distinguish between stable (denoted by growth of crystallites, tetragonal prismatic crystals, and platelets) and unstable (denoted by growth of needles and dendrites) crystal growth.…”