A study of the optical and polarisation properties of InGaN/GaN multiple quantum wells grown on a-plane and m-plane GaN substrates
| Autor: | Kundys, D., Sutherland, D., Davies, M., Oehler, F., Griffiths, J., Dawson, P., Kappers, M. J., Humphreys, C. J., Schulz, S., Tang, F., Oliver, R. A. |
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| Rok vydání: | 2016 |
| Předmět: | |
| Zdroj: | Science and Technology of Advanced Materials, 17, (2016) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1080/14686996.2016.1244474 |
| Popis: | In this paper we report on a comparative study of the low temperature emission and polarisation properties of InGaN/GaN quantum wells (QWs) grown on nonpolar a-plane and m-plane free-standing bulk GaN substrates where the In content varied from 0.14 to 0.28 in the m-plane series and 0.08 to 0.21 for the a-plane series. The low temperature photoluminescence spectra from both sets of samples are very broad with full width at half-maximum height increasing from 81 to 330 meV as the In fraction increases. Comparative photoluminescence excitation spectroscopy indicates that the recombination mainly involves strongly localised carriers. At a temperature of 10 K the degree of linear polarisation of the a-plane samples is much smaller than of the m-plane counterparts and also varies across the spectrum. From polarisation-resolved photoluminescence excitation spectroscopy we measured the energy splitting between the lowest valence sub-band states to lie in the range of 23-54 meV for both a-and m-plane samples in which we could observe distinct exciton features in the polarised photoluminescence excitation spectroscopy. Thus, the thermal occupation of a higher valence subband cannot be responsible for the reduction of the degree of linear polarisation. Time-resolved spectroscopy indicates that in a-plane samples there is an extra emission component which at least partly responsible for the reduction in the degree of linear polarisation. Comment: 9 pages 7 figures |
| Databáze: | arXiv |
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