synthetic single crystal tin lead disulfide (pbsns?) is a special member of layered transitional l dichalcogenides. similar to mos mose ws and wse adjacent layers are weakly coupled to each other and can be easily exfoliated (see images) and isolated down to monolayers. in the bulk it possesses 1.45 ev bａnd gap. physical properties of monolayer pbsns? are unknown both theoretically and experimentally. the first monolayer pbsns? has been synthesized at our facilities in late 2012 and the bulk crystals are perfected after two (2) years of development process.

　　crystals are up to 10mmx10mm in size and highly crystalline. ready for exfoliation to yield monolayers.

　　differences between the synthetic and the natural pbsns?;

　　- purity and magnetic properties: the synthetic pbsns? is 99.995% pure. diamagnetic semiconductor. the natural pbsns? is 98-99% pure and contains various impurities including anti-ferromagnetic iron oxides, ferromagnetic iron and nickel complexes. therefore, natural pbsns? is ferromagnetic semiconductor.

　　- defect profile and raman spectrum: the synthetic pbsns? contains least amount of defects. therefore, synthetic pbsns? has much sharper raman peaks.

　　- sub-bａnd gap: natural pbsns? possesses defect induced sub-bａnd gaps and enhanced exciton-phonon interaction.

　　- mechanical differences: natural pbsns? is more fragile compared to synthetic pbsns the mechanical stiffness and fragility stem from the increased density of defects.

　　- electrical properties: natural crystals have smaller grain sizes and the transport is mostly dominated by the variable-hopping and grain boundary scattering. synthetic materials possess conventional lightly-doped semiconductor behavior.