Speaker
Description
To investigate the potential barrier effect in the localized electric field of a quantum dot solar cell, we fabricated it with and without 2.8nm Al0.75Ga0.25As potential barriers. The localized electric fields of both structures with and without potential barriers were estimated using a fast Fourier transform of photoreflectance spectra. The signal of the wetting layer and Franz-Keldysh oscillation were increased with embedded Al0.75Ga0.25As potential barriers. An induced modulation efficiency increment caused this phenomenon, and the localized electric field of a sample with the potential barriers was smaller than without barriers due to the screening effect. When potential barriers were embedded, the localized electric field was affected by them, and it could be explained by the carrier confinement effect between the potential barriers. In addition, it was examined through the temperature dependency of photoreflectance spectra in detail. The localized electric field was increased with increasing temperature, which was caused by the photovoltaic effect.
