Mercury sulfide thin film deposition using [HgI 4 ] 2− complex ions

The optimal conditions for the growth of HgS films through the chemical bath deposition technique, using iodine as a complexing agent, are explored here, which has potential in semiconducting devices, for a diversity of applications. Some concentration variations were proposed to observe their effect on deposition, by changing the concentration ratios of sulfur and iodine to mercury. Variations were such that increasing iodine decreased sulfur, with mercury varying from 4.3 to 8.3%, relative to ([Hg]+[S]+[I]) content. It was observed that these variations control the heterogeneous reaction in different ways: increase in iodine concentration promotes the heterogeneous nucleation of HgS by the formation of [HgI4]2− complex ions; higher sulfur than iodine content degrades deposition; and doubling mercury concentration leads to a more uniform thin film. In addition, it was found that the used parameters generate films with predominant meta-cinnabar phase, and under certain conditions, the growth of cinnabar grains in preferential orientation can be favored.