Exciton states in wurtzite InGaN/GaN quantum wells: Strong built-in electric field and interface optical-phonon effects

摘要

Considering the strong built-in electric field (BEF) effects and large exciton-phonon interactions, we investigate the exciton states confined in an InGaN/GaN single quantum well (QW) by using the Lee-Low-Pines variational method. We find that the exciton state modification caused by the exciton-phonon interactions is remarkable. The exciton energy shift due to exciton-phonon interactions increases monotonically if the well width increases. With increasing the In fraction, the exciton energy shift firstly increases to a maximum, then decreases. The BEF has a significant influence on the exciton states in a QW with large well width. The physical reasons have been analyzed in detail. Good agreement for the zero-phonon peak energies and the Huang-Rhys factor has been obtained between our numerical results and the corresponding experimental measurements. (C) 2007 Elsevier Ltd. All rights reserved.