The only commercially available TlGaS2 vdW crystals have been synthesized at our facilities through float zone technique. TlGaS2 semiconductors belong to the thallium chalcogenides family with the chemical formula TlBX2 (where B=In or Ga, X=S, Se or Te). Members of this family have both layered (TlGaSe2, TlGaS2, TlInS2) and chain (TlInSe2, TlInTe2, TlGaTe2) structures. Stacking of the atoms in TlGaSe2, TlGaS2 and TlInS2 layered crystals is arranged in the form of two twisted anionic layers with the weak bonded Tl(+1) cations located in the trigonal cavities between them. In particular, TlGaS2 is a 2.45 eV direct gap semiconductor with strong optical and electronic anisotropy.
