Formation of ultrasmall semiconductor particles in Langmuir-Blodgett film precursors allowed one to reveal some new phenomena, quantum in nature, such as blue shift of the absorbance spectra [1, 2, 3] and single electron conductivity [4, 5]. It was also shown the possibility to aggregate these particles into thin layers by selective removal of the organic molecules .
The present study is dedicated to further probe the morphology and the in-plane electrical properties of such layers (CuS, ZnS, PbS) towards their possible future applications in electroptical devices of new design.
The formation of the particles and layers were monitored with quartz balance.
Brewster angle microscopy investigation of layers was performed after the deposition of the Langmuir-Blodgett films of fatty acid salts onto a glass solid support. Before the reaction with H2S a regular morphology and uniform covering was visible. After the reaction with H2S, the morphology of layer was strongly changed due to the formation of nanoclusters resulting in a rearrangement of the organic matrix. As the result initially uniform layer was transformed into a corrugated one. Film of aggregated particles prepared by selecting removal of organic molecules with chloroform was found to be composed of small aggregated crystals.
In-plane voltage-current characteristics, obtained from the aggregated layer of particles allowed one to estimate the specific resistance, which was found to be of the order of magnitude 100 Ohm x cm in the case of CuS hereby reported for the first time. The dependence of the conductivity upon the illuminating light wavelength is studied.
E.S. Smotkinm C. Lee, A.J. Bard, A. Campion, M.A. Fox, T.E. Mallouk, S.E.
Webber, and J.M. White, Chem. Phys. Lett., 153, 265-268 (1988).
C. Nicolini, Molecular Bioelectronics, World Scientific Publishing Co. Pte.
Ltd., Singapore, 1996.
P. Facci, V. Erokhin, A. Tronin, and C. Nicolini, J. Phys. Chem.,
98, 13323-13327 (1994).
V. Erokhin, P. Facci, S. Carrara, and C. Nicolini, J. Phys. D: Appl.
Phys., 28, 2534-2538 (1995).
P. Facci, V. Erokhin, S. Carrara, and C. Nicolini,Proc. Natl. Acad. Sci.
USA, 93, 10556-10559 (1996).