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Carrier Lifetime Measurements in Semiconductors through the Microwave Photoconductivity Decay Method
Published on: April 18, 2019
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Charge carrier thermalization in organic diodes.
N J van der Kaap1, L J A Koster1
1Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands.
Scientific Reports
|January 22, 2016
Summary
Energetically hot carriers in organic semiconductors quickly relax, minimally impacting device operation. Photo-generated carriers slightly increase mobility, showing limited effects on charge transport properties.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Organic Electronics
Background:
- Organic semiconductor charge carrier mobilities are typically measured assuming steady-state equilibrium.
- Energetically hot carriers, introduced by photo-excitation or injection, can perturb this equilibrium.
Purpose of the Study:
- To investigate the effect of energetically hot carriers on charge transport in organic semiconductors.
- To quantify the impact of hot carriers on mobility measurements.
Main Methods:
- Steady-state kinetic Monte Carlo simulations were employed.
- Analysis focused on carrier relaxation times and mobility changes.
Main Results:
- Injected hot carriers in organic semiconductors undergo rapid energetic relaxation (tens of nanoseconds).
- This relaxation is significantly faster than typical carrier transit times.
- Photo-generated carriers led to a modest increase in mobility (factor of 1.1) in organic photovoltaic materials.
Conclusions:
- The impact of energetically hot carriers on normal device operation is generally limited.
- Rapid relaxation minimizes the perturbation of equilibrium charge transport.
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