Hot Carrier Relaxation and Phonon Dispersion in III-V Alloys
| Autor: | Smyth, T., Yagi, S., Wang, Y., Dvorak, M., Tayebjee, M., Fabien, C., Gunning, B., Xia, H., Feng, Y., Tessarek, C., Latzel, M., Heilmann, M., Chang, C.-W., Wadekar, P., Tu, L.W., Shrestha, S., Bremner, S., Huang, S., Doolittle, W.A., Schmidt, T.W., Sugiyama, M., Christiansen, S., Conibeer, G.J. |
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| Jazyk: | angličtina |
| Rok vydání: | 2014 |
| Předmět: | |
| DOI: | 10.4229/eupvsec20142014-1bv.7.57 |
| Popis: | 29th European Photovoltaic Solar Energy Conference and Exhibition; 316-321 The hot carrier solar cell is an approach that will circumvent the Shockley-Queisser limit by extracting ‘excess’ energy charge carriers from the cell absorber before they can thermalize with the lattice. Aiming to construct such an absorber, the current work finds support for decay-blocking of zone-centre optical phonons, building up a non-equilibrium phonon population that will continually re-supply carriers with energy until collection. Such a bottleneck relies on pathways classifiable under either phonon decay blocking or phonon/carrier constriction. The so-called Klemens decay mechanism can be limited by use of a medium with large phonon band gap such as InN, and carrier and phonon transport can be delayed within multiple quantum well superlattices based in III-V material systems. To minimize lattice mismatch and simplify fabrication, investigation has been carried out into InGaAs and InGaN alloy combinations, either of which can be used to build a device widely varying in electronic barrier height throughout its structure. We utilize femtosecond-resolved photoluminescence to measure carrier relaxation times in these materials and employ Raman scattering spectroscopy together with Inelastic X-ray Scattering to map the relevant phonon dispersions. |
| Databáze: | OpenAIRE |
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