Carrier-tunneling-induced photovoltaic effect of InAs/GaAs quantum-dot solar cells
Abstract
This study reports the observation of the carrier-tunneling-induced photovoltaic (PV) effect in an InAs/GaAs quantum-dot solar cell (QDSC). The illuminated current-voltage (J-V) characteristics and the applied-bias-dependent electroreflectance (ER) were measured at 12 K by using an excitation laser with a wavelength of 975 nm (1.27 eV), which excites only the quantum-dot (QD) states below the GaAs band gap. The J-V results showed a peculiar current curve in the reverse bias region caused by carrier tunneling. The ER results showed that the junction electric field ( F) decreased with increasing intensity of the excitation laser ( I ex ) at different applied-bias-voltages ( V a ) due to the tunneling-induced PV effect. The PV effect was enhanced by improved tunneling with increasing reverse bias voltage. We also evaluated the tunneling carrier density ( σ pv ) as a function of V a in the QDSC.
- Publication:
-
Journal of Korean Physical Society
- Pub Date:
- August 2016
- DOI:
- 10.3938/jkps.69.566
- Bibcode:
- 2016JKPS...69..566L
- Keywords:
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- Tunneling;
- Electroreflectance;
- Photovoltaic effect;
- Solar cell;
- Carrier density