Time-resolved spectroscopy on GaN nanocolumns grown by plasma assisted molecular beam epitaxy on Si substrates

P. Corfdir (1) , Pierre Lefebvre (1, 2) , J. Ristic (1, 3) , Pierre Valvin (2) , E. Calleja (3) , A. Trampert (4) , Jean-Daniel Ganière (1) , Benoit Deveaud-Plédran (1)

1 Institut de Photonique et d'Electronique Quantiques
2 GES - Groupe d'étude des semiconducteurs
3 Departamento de Ingeniería Electrónica and ISOM
4 PDI - Paul-Drude-Institut für Festkörperelektronik

A detailed study of excitons in unstrained GaN nanocolumns grown by plasma assisted molecular beam epitaxy on silicon substrates is presented. The time-integrated and time-resolved photoluminescence spectra do not depend significantly on the (111) or (001) Si surface used. However, an unusually high relative intensity of the two-electron satellite peak of the dominant donor-bound exciton line is systematically observed. We correlate this observation with the nanocolumn morphology determined by scanning electron microscopy, and therefore propose an interpretation based on the alteration of wave functions of excitonic complexes and of donor states by the proximity of the semiconductor surface. This explanation is supported by a model that qualitatively accounts for both relative intensities and time decays of the photoluminescence lines.

Domaines: Autre [cond-mat.other]

P. Corfdir, Pierre Lefebvre, J. Ristic, Pierre Valvin, E. Calleja, et al.. Time-resolved spectroscopy on GaN nanocolumns grown by plasma assisted molecular beam epitaxy on Si substrates. Journal of Applied Physics, 2009, 105, pp.013113. ⟨10.1063/1.3062742⟩. ⟨hal-00390003⟩