Used Chemicals

The arsenic used (product of Laboratoires de la Vielle, Belgium) was of semiconductor purity (5N) and was stored in sealed ampoules until needed. The surface oxide layer was removed by sublimation of As$_2$O$_3$ immediately before usage. To improve purity of the sulphur (product of Lachema Brno, Czech Republic) used in this experiment, it was distilled in house three times. Triethylamine (TEA), Propylamine (PA), Dimethylsulfoxide (DMSO), Dimethylformamide (DMF), and other solvents as Methanol and Acetone are all products of Aldrich or Fluka Chemicals, all of them are at least p.a. purity chemicals.