Heterocrystals of metal dichalcogenides and Bi2S3, Bi2Se3 or Bi2Te3 are presented, in which the metal dichalcogenides and Bi2S3, Bi2Se3 or Bi2Te3 do not largely retain their independent properties. These heterocrystals exhibit electronic and optical changes, which make them attractive for beyond-silicon electronics and optoelectronics. Particularly, these heterocrystals can be re-configured in a manner that allows bit writing and pattern drawing. Embodiments of these heterocrystals, methods of forming these heterocrystals, methods of reconfiguring the heterocrystals, information storage devices, optoelectronic circuits and photonic crystals are presented.