Youngquist, M. G. and Baldeschwieler, J. D. (1991) Observation of negative differential resistance in tunneling spectroscopy of MoS2 with a scanning tunneling microscope. Journal of Vacuum Science and Technology B, 9 (2). pp. 1083-1087. ISSN 1071-1023. http://resolver.caltech.edu/CaltechAUTHORS:YOUjvstb91a
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A scanning tunneling microscope has been used for imaging and tunneling spectroscopy of 2Hb–MoS2 in ultrahigh vacuum. Atom-resolved images obtained in three distinct imaging modes–measuring z at constant current, barrier height at constant current, and current at constant z–are presented. Current–voltage (I–V) tunneling spectra reveal the occasional presence of negative differential resistance. Possible origins of the effect are discussed. Convolution of the sample energy density of states (DOS) with a contamination-induced peak in the tip DOS is the probable cause. Other mechanisms that may be active include charging of electron traps in the barrier or on the tip, and resonant tunneling in a double-barrier quantum well structure resulting from layer separation in the MoS2 crystal.
|Additional Information:||© 1991 American Vacuum Society. Received 24 July 1990; accepted 5 September 1990. J.A. Kramar and M.R. Weimer laid the foundation for this work in their extensive study of MoSz with the STM. JAK and R.J. Driscoll helped with the initial sample preparation and characterization, and both helped introduce MGY to the UHV STM system. MGY is a Department of Education Fellow. This work was supported by grants from the ONR, NSF, and the Shell Companies Foundation.|
|Subject Keywords:||SCANNING TUNNELING MICROSCOPY, ELECTRON TUNNELING SPECTROSCOPY, MOLYBDENUM SULFIDES, IV CHARACTERISTIC, IMAGE FORMING, BARRIER HEIGHT, ENERGY–LEVEL DENSITY, QUANTUM WELL STRUCTURES|
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|Deposited On:||21 Dec 2008 03:23|
|Last Modified:||26 Dec 2012 10:39|
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