As2S3 comes in perfect 2:3 stoichiometry.

As2S3 comes in perfect 2:3 stoichiometry. After 250 growth trials in 3 years, perfect stoichirometry, large domain size, minimal defect density (1 parts in 100,000 unit cells), and perfected purity level (99.9998%) are achieved. In the bulk form, arsenic sulfide (As2S3) is a direct gap semiconductor and has band-gap at around 2.5 eV. Similar to molybdenum disulfide, it has layered structure (lamellar) with weak interlayer coupling and can be isolated down to monolayers. The monolayer thickness measures ~0.8 nm and the monolayer As_S_ is waiting to be discovered both experimentally and theoretically. Our crystals are large in size ~8mm and show remarkable PL characteristics. Our crystals are grown by state-of-the-art growth techniques over 8 weeks and show high crystallinity. Raman spectrum displays very sharp and clear modes with FWHM less than 6cm-1. As2S3 comes ready for exfoliation and is ideal for 2D research.
 
Space group: P21/c
Layered: Yes / Exfoliates to monolayers
Bａnd gap: ~2.2 eV in bulk
Purity: Semiconductor grade (6N) 99.9999%
Growth technique: Bridgman-Stockbarger
Sample size: ~1 cm