Effects of pressure and temperature on exciton absorption and band structure of layer crystals: Molybdenum disulphide

摘要: Abstract The effect of pressures up to 60 kbars on the exciton series in spectral region 2 eV molybdenum disulphide has been investigated at room and liquid nitrogen temperatures, using a diamond anvil device. An electronic band model, suggested by crystallography layered material optical spectra various polytypes, is made basis for discussion experimental results. indirect energy gap 0.25 determines electrical properties intrinsic material, but transitions from lower, spin-orbit split valence produce fundamental absorption edge. It shown that under these circumstances pressure coefficient an peak can be separated into two parts; direct dependence binding which result changes free carrier density are necessarily related variation gap.