Tetrathiafulvalene-based conducting deposits on silicon substrates

Abstract

Tetrathiafulvalene-based molecular conductors, namely [TTF][TCNQ], (TTF) 6 [N(C 2 H 5 ) 4 ](HPM 12 O 40 ) (M ~W, Mo), and TTF[Ni(dmit) 2 ] 2 have been processed as thin films on microrough (001)-oriented silicon substrates using three different techniques. CVD-grown [TTF][TCNQ] deposits consist of platelets (10 6 5 mm) and filaments (diameter y1 mm). CN stretching modes in the infrared spectrum and CC stretching modes in the Raman spectrum are in agreement with a charge transfer of y0.6 from the TTF donor to the TCNQ acceptor. The N(1s) photoelectron spectrum confirms the presence of a reduced tetracyanoquinodimethane moiety. The films exhibit a semiconducting behaviour with a room-temperature conductivity of y0.4 S cm 21 . Deposits of (TTF) 6 [N(C 2 H 5 ) 4 ](HPW 12 O 40 ) are electrodeposited on microrough Si(001) at constant current from TTF and [N(C 2 H 5 ) 4 ] 3 (PW 12 O 40 ) in acetonitrile solution. The films are made of stacked sheets (5 v thickness v 25 mm). Vibrational spectra, conductivity measurements and magnetic susceptibility data are similar to those obtained on single crystals of (TTF) 6 [N(C 2 H 5 ) 4 ](HPW 12 O 40 ) grown on a platinum electrode. Thin films of TTF[Ni(dmit) 2 ] 2 are grown on microrough Si(001) by an adsorption process in organic solution. The deposits are characterized by Raman micro-probe and exhibit a pseudo-metallic behaviour with a room-temperature conductivity of about 2 S cm 21 .

Thin films of molecular materials synthesized from fisher's carbene ferrocenyl: Film formation and electrical properties

“…Fig. 4b shows that the main difference between the simples occurs after 10 V. This voltage value is within the range that is commonly used in analog and digital devices, so that thin-films of synthesized materials may be used in device applications requiring conductivity changes along some favored direction [18,19].…”

TTF[Ni(dmit)2]2: From single-crystals to thin layers, nanowires, and nanoparticles

“…The first attempts to grow films of TTF[Ni(dmit) 2 ] 2 used a dipping process and stainless steel conversion coating, silicon conversion coating, or microrough silicon as substrates [81,82].…”

Electrical and optical properties of (PPh4)2[Fe(CN)5NO] non-crystalline thin films prepared with the vacuum thermal evaporation technique

“…It may be difficult to envision a technological breakthrough while using them in their usual, single-crystalline form, but the thin-film production of such materials offers an attractive alternative [2][3][4][5][6][7]. Recent research work has been oriented to the formation and characterization of molecular-material thin films with probable photonic, optoelectronic or electronic-device applications [8,9].…”

“…A regular stacking of molecules, such as is found in molecular materials, may permit the formation of semiconducting, conducting or superconducting thin films. Therefore, in order to describe the relationship between the physical configuration and the electrical properties of the thin films, it is necessary to produce such systems with a welldefined microstructure [1][2][3][4][5][6][7][8][9].…”