The electronic structure of metal/alkane thiol self-assembled monolayers/metal junctions for magnetoelectronics applications

Abstract

Burst, J.M.; Thornburg, S.N.; Ventrice, C.A. Jr.; Zhang, Chunjuan; Redepenning, Jody G.; Losovyj, Yaroslav B.; Rosa, Luis G.; Dowben, Peter A.; and Doudin, Bernard, "The electronic structure of metal/alkane thiol self-assembled monolayers/metal junctions for magnetoelectronics applications" (2003). Jody Redepenning Publications. 2.

Orientation and bonding of biphenyldimethyldithiol

“…Misorientation and imperfections in the molecular films have been suggested to have an enormous influence on the tunnelling characteristics through alkane thiol films [6]. Although we are limited to speculation, it may be that the underlying metal substrate strongly influences tunnelling from occupied states in molecular conductance spectroscopy, particularly if there are defects in the molecular overlayer; thus comparison with photoemission is difficult.…”

“…Although they are very popular as candidates for use in junction devices, there are clearly problems associated with the use of alkane thiols [6]. Biphenyl and terphenyl functionalized by one or two thiols and one or two methyl groups have been extensively investigated [7][8][9][10][11][12][13][14] by x-ray photoemission spectroscopy (XPS), reflection absorption infrared (RAIR) spectroscopy, near-edge x-ray absorption fine structure (NEXAFS) spectroscopy, scanning tunnelling microscopy (STM), ellipsometry and advancing the water contact angle.…”

The interface electronic structure of thiol terminated molecules on cobalt and gold surfaces

“…Although very popular as candidates for junction devices, there are clearly problems associated with the use of alkane thiols [16,55,56]. Biphenyl and terphenyl functionalized by one or two thiols and one or two methyl groups, have been extensively investigated [55][56][57][58][59][60][61][62][63][64][65][66][67][68] by X-ray photoemission spectroscopy (XPS), refl ection absorption infrared spectroscopy (RAIR), nearedge X-ray absorption fi ne structure spectroscopy (NEX-AFS), scanning tunneling microscopy (STM), ellipsometry and advancing water contact angle.…”

“…The majority of molecules being considered for the classical molecular electronic devices contain various alkane [2,16,48] and polyphenyl combinations [2,49,50] functionalized with endgroups such as thiols (H-S-), amines (H 2 -N-) and/or cyano (C-N) [2,[51][52][53]. Not surprisingly, the majority of experimental effort and complementary theoretical work has addressed the bonding and adsorption of these organic layers on gold surfaces, and to a lesser extent, silver surfaces.…”

“…The ability to utilize the unique structural and electronic properties of self-assembled monolayers (SAMs) in nano scale electronics is more recent and has rarely included consideration of spin. Nonetheless, new dielectric barrier layers for magneto-resistive junctions are being aggressively sought [7] and organic layers may provide many unique opportunities [8][9][10][11][12][13][14][15] in spite of their many diffi culties [16][17][18].…”