ELECTRICAL-PROPERTIES OF MOLYBDENUM-DISULFIDE MOS2 - EXPERIMENTAL-STUDY AND DENSITY-FUNCTIONAL CALCULATION RESULTS

Molybdenum disulfide is a very interesting material with numerous appl ications. However, to our knowledge, very few experimental works invol ving electrical measurements have been performed with this material up to now. This paper is devoted to the characterization of conduction m echanisms in thin layers and pressed pellets. The electronic structure related to the lubricating properties and the activation energy are d etermined using theoretical calculations (density functional theory) a nd experimental methods. A good agreement is found between the theoret ical predictions and the experimental results. D.c. and a.c. conductiv ities 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 form ula sigma(ac)(omega) = A omega(n), where the slope n is close to 0.8. (C) 1997 Elsevier Science S.A.