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Field-effect-modulated Seebeck coefficient in organic semiconductors.
K P Pernstich1, B Rössner, B Batlogg
1Laboratory for Solid State Physics, ETH Zurich, CH-8093 Zurich, Switzerland. pernstich@mat.ethz.ch
Nature Materials
|February 26, 2008
Summary
Researchers measured the Seebeck coefficient in organic semiconductors, finding it comparable to inorganic materials. This reveals similar charge transport mechanisms and band-like quasiparticle behavior in both organic and inorganic semiconductors.
Area of Science:
- Organic electronics
- Semiconductor physics
- Materials science
Background:
- Charge and energy transport in organic semiconductors are crucial for device operation.
- The Seebeck coefficient (S) offers insights into charge carrier dynamics and electronic contributions.
- Understanding these properties is key to advancing organic electronic and optoelectronic technologies.
Purpose of the Study:
- To measure the temperature- and carrier-density-dependent thermopower in organic semiconductors.
- To investigate the nature of charge carrier transport in these materials.
- To compare transport mechanisms in organic and inorganic semiconductors.
Main Methods:
- Utilized a field-effect geometry to modulate the chemical potential in organic semiconductor crystals and thin films.
- Measured the Seebeck coefficient (S) as a function of temperature and carrier density.
- Analyzed thermopower data to understand charge and entropy transport.
Main Results:
- Successfully measured temperature- and carrier-density-dependent thermopower in two prototypical organic semiconductors.
- Observed Seebeck coefficients within the range typical for inorganic semiconductors.
- Demonstrated that charge and entropy transport can be described by band-like transport of quasiparticles with scattering and in-gap trap states.
Conclusions:
- Organic and inorganic semiconductors exhibit surprisingly similar charge transport mechanisms.
- Band-like transport of quasiparticles, influenced by scattering and trap states, governs charge and entropy transport in these organic materials.
- The Seebeck coefficient is a valuable tool for characterizing charge transport in organic electronics.
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