XPS AND STS OF LAYERED SEMICONDUCTOR MOSX

Joint use of XPS and STS methods for MoS(X) van der Waals face cleaned by removal of a few layers in air have allowed to determine the connection between change of electronic properties and variation in Mo content for MoS(X) surface layers . STS results (I-V curves with electron transport across MoS(X) layers) show the p-type conductivity for MoS2; p- and n- regions for MOS 1.6 The surface state density is higher for p- MOS1.6 than for P-MoS2. From I-V curve with electron transport along layers for MOS 1.6 surface the bandgap above 1.1 eV and \E(f) - E(c)\ congruent-to 0.4 eV are determined. For results explanation we assume that: surface states creation occurs due to top layer defects formation under top layer breaks ; n- type regions creation is caused by growth of concentration of donor centers associated with excess Mo atoms.