Room Temperature Negative Differential Resistance through Individual Organic Molecules on Silicon Surfaces

• Published in: Nano letters 2004-01, Vol.4 (1), p.55-59
• Main Authors: Guisinger, Nathan P, Greene, Mark E, Basu, Rajiv, Baluch, Andrew S, Hersam, Mark C
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Electron and ion emission by liquids and solids; impact phenomena; Electron, ion, and scanning probe microscopy; Exact sciences and technology; Impact phenomena (including electron spectra and sputtering); Photon- and electron-stimulated desorption; Physics; Scanning probe microscopy: scanning tunneling, atomic force, scanning optical, magnetic force, etc; Structure of solids and liquids; crystallography
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/nl0348589

Room temperature negative differential resistance (NDR) has been measured through individual organic molecules on degenerately doped Si(100) surfaces using ultrahigh vacuum scanning tunneling microscopy (STM). For styrene molecules on n-type Si(100), NDR is observed only for negative sample bias because positive sample bias leads to electron stimulated desorption. By replacing styrene with a saturated organic molecule (2,2,6,6-tetramethyl-1-piperidinyloxy), electron stimulated desorption is not observed at either bias polarity. In this case, NDR is observed only for negative sample bias on n-type Si(100) and for positive sample bias on p-type Si(100). This unique behavior is consistent with a resonant tunneling mechanism via molecular orbitals and opens new possibilities for silicon-based molecular electronic devices and chemical identification with STM at the single-molecule level.