Nanocomposites and nanomaterials

Barrier properties of nanostructures GaP/PEDOT:PSS
T.R. Barlas, O.S. Kondratenko, N.V. Kotova, T.S. Lunko, I.B. Mamontova, S.V. Mamykin, V.R. Romanyuk, M.I. Taborska
V. Lashkaryov Institute of Semiconductor Physics National Academy of Sciences of Ukraine. prospect Nauky, 41, Kyiv, 03028, Ukraine.
E-mail: barlas@isp.kiev.ua

The most popular organic conductor today is the PEDOT:PSS composite. It is widely used in organic electronics, in particular to create photosensitive heterostructures such as organic/inorganic semiconductors, which are easy to manufacture due to the vacuum-free, low-temperature technology, and promising characteristics [1, 2]. GaP (111), n-type single crystals were used for the fabrication of hybrid hetero- structures based on gallium phosphide and charge selective organic layer PEDOT:PSS. Deposition of organic films was carried out by spin coating followed by heating at T = 140-150ºC and washing of PEDOT:PSS films in ethanol. The thickness of the fabricated films determined by spectral ellipsometry was in the range of 40-70 nm. The back ohmic contacts were made by applying indium on the reverse side of the sample with prior removal of the oxide layer and sulfidation of the surface. The front contacts were created by physical vapor deposition of silver.
Dark and light current-voltage characteristics (with irradiation power 136 mW/cm2) of fabricated heterostructures were measured. The value of the ideality factor n obtained from dark I-V characteristics was in the range of n = 1.5–2.5. Saturation currents Io were in the range of Io=10-9-10-11 A/cm2. The value of the open circuit voltage Uoc was within 1-1.1 V. The results for PEDOT:PSS/GaP heterostructures show that they have good barrier characteristics and further studies of these structures are promising. These may include, in particular, interface structuring, and the introduction of additional plasmon-active metal nanoparticles. Previous studies of similar heterostructures, based on nanoporous gallium phosphide and PEDOT: PSS charge-selective organic layer have shown that they are also barrier structures, but their characteristics depend significantly on the structure of the porous layer and further studies are needed to improve them.

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