Indirect interband transition in hexagonal GaN

O Lancry (1) , J.-L Farvacque (1) , E Pichonat (1) , Christophe Gaquière (2)

1 Université de Lille, Sciences et Technologies
2 IEMN - Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520

In this paper, we report on optical investigations with Raman experiment to underline a new Ultra Violet (UV) luminescence band in hexagonal Gallium Nitride (GaN) at 4.56 eV. GaN is a direct band gap semiconductor, the photoluminescence peak corresponding to the energy gap at 3.43 eV dominates the spectrum. Nevertheless, other electronic interband transitions can appear on the spectrum: the electronic indirect interband transitions. We attribute one of them to the observed new photoluminescence band at 4.56 eV. This interpretation is supported by photoluminescence spectra obtained on three different samples at room temperature and at-50°C with UV excitation source: mbd-266 nm solid laser (4.66 eV) and by the study of three criteria: the partly opposite parities of initial and final wave function, the implication of acoustic phonons and temperature control.

Mots clés: Physical Sciences; Physical Sciences

O Lancry, J.-L Farvacque, E Pichonat, Christophe Gaquière. Indirect interband transition in hexagonal GaN. Journal of Physics D: Applied Physics, 2011, 44 (7), pp.75105. ⟨10.1088/0022-3727/44/7/075105⟩. ⟨hal-00594972⟩