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The electrical, optical, and metal-semiconductor contact properties of the polyaniline prepared by emulsion polymerization have been investigated to obtain an organic semiconductor material. The obtained results suggest that the polyaniline (PANI) studied is an organic semiconductor material with optical band gap (E(g) = 2.21 eV) and room electrical conductivity (sigma(25) = 3.12 x 10(-2) S/cm) values. A Schottky diode with configuration Ag/PANI/n-Si was fabricated. The ideality factor and barrier height of Ag/PANI/n-Si diode at room temperature were found to be 4.59 and 0.38 eV, respectively. The obtained diode parameters change with temperature. The Richardson constant A* value for the Ag/PANI/n-Si diode was found to be 3.81 x 10(-4) A/cm(2).K. The Ag/PANI/n-Si diode is a metal-insulator-semiconductor-type device. The standard deviation, which is a measure of the barrier homogeneity, was found to be 0.14, indicating the presence of interface inhomogeneities. It can be concluded that the polyaniline prepared by emulsion polymerization is an organic semiconductor and Ag/PANI/n-Si configuration shows a Schottky contact.

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Article Title: Very high two-dimensional hole gas mobilities in strained silicon germanium Year of publication: 1994 Link to published version: http://dx

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The temperature dependences of the dielectric constants of the ferroelectric semiconductors TlInS2 and TlGaSe2 have been studied following their annealing within the incommensurate phase. Unusual memory effects accompanied by both a remarkable inflection of the temperature dependence curves in the incommensurate phase and various shifts of the incommensurate (Ti) and commensurate (Tc) phase transition temperatures have been revealed in both crystals. The observed effects are explained on the basis of a defect density wave model taking into account the interaction of modulation waves with charge carriers localized at impurity states. The thermally activated population of these states during the heating or cooling processes is responsible for the changes of the phase transition temperatures.