Abstract
The effect of excitons in Al<inf>x</inf>Ga<inf>1-x</inf>As/GaAs superlattice solar cells has been investigated. We have shown that the superlattice active layers are effective to improve the solar cell performances because of the exciton enhanced photo-absorption. External quantum efficiency spectra show sharp and intense increase at the absorption edge due to excitonic absorption. This result indicates that excitonic photo-absorption can be stabilized at room temperature by using a superlattice structure. Optical properties of superlattice solar cells depend on the superlattice parameters because they determine the excitonic confinement effect, the tunneling effect and the sub-band structure. In this study, we compare external quantum efficiency for solar cells with different superlattice parameters to optimize the structure. The optimal barrier layer thickness is determined to be 1 nm for the Al<inf>0.5</inf>Ga<inf>0.5</inf>As/GaAs superlattice solar cell with 2-μm-thick active layer.
| Original language | English |
|---|---|
| Pages (from-to) | 333-336 |
| Number of pages | 4 |
| Journal | Journal of Crystal Growth |
| Volume | 425 |
| DOIs | |
| Publication status | Published - 2015 Jul 28 |
Keywords
- A3. Molecular beam epitaxy
- A3. Superlattices
- B2. Semiconducting gallium arsenide
- B3. Solar cells
ASJC Scopus subject areas
- Condensed Matter Physics
- Materials Chemistry
- Inorganic Chemistry