Organic semiconductor frequency characteristics

These expressions can be used to derive the nearly total reflectance of metals below their plasma frequency. A similar characteristic frequency dependence of a(o)) and e((o) may be seen in semiconductors where oip depends the electron density in the fliled valence band. The conduction electrons can oscillate as a collective mode (plasma oscillation). A plasmon is a quantized plasma oscillation. The frequency and wavevector dependence of plasmons in one-dimensional metals have been predicted (458, 576) to be qualitatively different from those of three-dimensional metals. Recent direct measurements (552) of plasmons in the one-dimensional organic metal tetrathiofulvalinium-tetracyano-quinodimethanide (TTF)(TCNQ) are qualitatively consistent with some of the predictions assuming a tight-binding band (576). 

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