Abstract
We report a comprehensive photoluminescence excitation (PLE) investigation of the deep iron acceptor in hexagonal GaN. PLE spectra of the (G) (S)] luminescence in semi-insulating GaN samples reveal intracenter excitation processes via excited states of the center. Zero-phonon lines resolved around 2.01 and at 2.731 eV are attributed to the (S) (G) and the (S) E(G) transition, respectively. A steplike excitation structure on the low-energy onset of the charge-transfer band is attributed to the formation of a (,e,h) complex at 2.888 eV. We estimate a binding energy of 280 meV locating the deep acceptor level 3.17 eV above the valence-band maximum. In n-type GaN samples the luminescence is excited by hole-transfer processes. The experimental results indicate that the internal reference rule fails for the GaN/GaAs heterostructure.
- Received 17 June 1996
DOI:https://doi.org/10.1103/PhysRevB.55.4382
©1997 American Physical Society