Annealing studies on GaN hydride vapor phase epitaxial layers

• Published in: Solid state communications Vol. 109; no. 11; pp. 683 - 686
• Main Authors: Reynolds, D.C., Look, D.C., Wille, T., Bajaj, K.K., Collins, T.C., Molnar, R.J.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 03.03.1999; Elsevier
• Subjects: A. Disordered systems; B. Crystal growth; C. Impurities in semiconductors; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Iii-v semiconductors; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Photoluminescence; Physics; B. Crystal growth; C. Impurities in semiconductors; A. Disordered systems; Annealing; Inorganic compounds; Epitaxial layers; Semiconductor materials; Line shape; Gallium nitrides; Thick films; Phonons; Photoluminescence; Binary compounds; Experimental study; Replicas; Energy-level transitions; Acceptor donor pair; Binding energy; Donor center; Bound exciton
• ISSN: 0038-1098; 1879-2766
• DOI: 10.1016/S0038-1098(99)00016-2

A dramatic change is observed in the photoluminescence spectrum of a GaN sample after annealing at a temperature of ∼835°C. The as-grown sample, and the same sample annealed at 830°C, show a single dominant donor-bound-exciton (D 0, X) emission line. After annealing at ∼835°C, the emission evolves into at least four broader emission lines. Increasing the annealing temperature to 840°C reverses the emission spectrum back to the single D 0, X line. Repeating the 835°C anneal again produces the evolved spectrum. We propose a model that can account for all of the spectral lines that are generated by the 835°C anneal. We also suggest some possible explanations for the dramatic changes that occur in the emission spectrum when the annealing is carried out over small temperature intervals.