Langmuir-Blodgett films based on cyanacrylic acid as dielectric coatings on semiconductors

The dielectric properties of Langmuir-Blodgett films (LBF) of hexa-cyanacrylic acid (C₆-CAA) were investigated by ellipsometry and current-voltage and Faraday-voltage characteristics of metal-insulator-metal (MIM) and metal-insulator-semiconductor (MIS) structures. The layer-type application nature of these films of monolayer thickness 1.1 nm is demonstrated. The refractive index of LBF of C₆CAA is equal to 1.43 in the body of the film, and increases to 1.46 in the vicinity of the interface with silicon. The current transfer mechanism in LBF is determined by tunnelling processes involving local centres in the film. The surface charge in the MIS structure with LBF of C₆-CAA on Si is localised in a transitional hydrophobic layer on the silicon surface; the magnitude and stability of this charge are determined by the technology of fabricating the Si surface before hydrophobization. An attempt was successfully made to passivate the surface of the semiconductor Cd_xHg_1-xTe LBF C₆-CAA. A negative surface charge of density 4×10¹⁵ m^-2 was detected in this system.