Electrical properties of molybdenum disulfide MoS2.: Experimental study and density functional calculation results

Molybdenum disulfide is a very interesting material with numerous applications. However, to our knowledge, very few experimental works involving electrical measurements have been performed with this material up to now. This paper is devoted to the characterization of conduction mechanisms in thin layers and pressed pellets. The electronic structure related to the lubricating properties and the activation energy are determined using theoretical calculations (density functional theory) and experimental methods. A good agreement is found between the theoretical predictions and the experimental results. D.c. and a.c. conductivities are measured in the frequency range 10-10(7) Hz. The electronic transport mechanism is discussed in terms of Mott hopping in samples. The a.c. conductivity at high frequencies can be expressed by the formula sigma(ac)(omega) = A omega(n), where the slope n is close to 0.8. (C) 1997 Elsevier Science S.A.