The interactions of electrons with organized organic films studied by photoelectron transmission

Electron transmission through organized organic thin films—the effect of their structure on the electronic band

“…The low-energy part (<1 eV) of the transmission curve (Fig. 1B) is consistent with earlier results obtained in photoelectron spectroscopy by the retarding field method for LB films of CdAr and arachidic acid [16,17]. These results indicated that for OOTF, on a scale of up to about 10 nm, inelastic collisions were of minor importance, suggesting that the transmission of low-energy electrons (<0.8 eV) was controlled mainly by an electrostatic barrier perpendicular to the surface.…”

“…As was demonstrated in Ref. [17], in the case of electron transmission through thin well-organized organic films with a thickness of up to about 15 nm, less than 10% of the transmitted electrons suffered inelastic collision. process is the sharp low-energy cut-off in the transmitted electron energy spectrum as seen in Figs 1 and 3.…”

The role of three dimensional structure in electron transmission through thin organic layers

“…electrons. This type of energy dependent transmission indicates the existence of band structure in the film, as was shown in former studies, 19,12 with the bottom of the conduction band at V 0 . While in the three layered case the peak of the energy distribution of electrons transmitted through the CdAr is at higher energy than for CdBr, in the nine layered film the order is reversed.…”

“…Similar behavior is expected for films of saturated hydrocarbon chains of various lengths. 10 In previous studies 11,12 we have demonstrated that thin organized organic films are transparent to electrons of energy higher than 0.8 eV ͑above the vacuum energy͒, and Sanche has commented that this onset of unity transmittance is associated with the position at V 0 ϭ0.8 eV of the conduction band edge in hydrocarbon crystals. 13 Clearly the order due to the periodicity of the repeating functional groups in the direction perpendicular to the surface, namely, the direction at which the velocity is measured ͑the Z direction͒, is important for the band formation and is essential for efficient ET.…”

“…12 The OOTFs were prepared by the Langmuir-Blodgett ͑LB͒ method 14 and transferred to a quartz microscope slide coated with a 150 nm thick gold film. Three type of organic films were prepared-cadmium arachidate ͑CdAr; CH 3 ͑CH 2 ͒ 18 COO Ϫ ͒ 2 Cd 2ϩ ͒, cadmium salt of brassidic acid ͑CdBr; ͑CH 3 ͑CH 2 ͒ 7 CHϭCH͑CH 2 ͒ 11 COO Ϫ ͒ 2 Cd ϩ2 ͒, and a film which consists of a 1:1 mix of both.…”