Synthesis and some properties of black phosphorus single crystals

Black phosphorus single crystals were prepared from a solution of white phosphorus in liquid bismuth. The temperature dependence of the electrical resistivity and magnetoresistivity, and the reflection spectrum at room temperature were measured. The intrinsic band gap energy was estimated to be 0.31 eV and negative magnetoresistance was observed at 4.2 K. Intercalation of AsF5 to black phosphorus was tried and several-fold increase in the electrical conductivity was observed.