Dynamics of bound‐exciton luminescences from epitaxial GaN

L. Eckey, J.‐Ch. Holst, P. Maxim, R. Heitz, A. Hoffmann, I. Broser, B. K. Meyer, C. Wetzel, E. N. Mokhov, P. G. Baranov
1996 Applied Physics Letters  
Free-and bound-exciton luminescences of GaN epitaxial layers grown by a sublimation technique on 6H-SiC substrates were investigated using time-integrated and time-resolved photoluminescence measurements at low temperatures. Lifetimes were determined for the donor-bound exciton at 3.4722 eV and for two acceptor-bound excitons with energies of 3.4672 eV and 3.459 eV. On the basis of our results we obtain an upper limit of the free-exciton oscillator strength of 0.0046 for GaN. Luminescences
more » ... en 3.29 eV and 3.37 eV are identified as due to excitons deeply bound to centers located near the substrate-epilayer interface. Free excitons are captured by these centers within 20 ps.
doi:10.1063/1.116703 fatcat:fwda4cykzrhmflokhrj5moeq6a