Direct determination of the silicon donor ionization energy in homoepitaxial AlN from photoluminescence two-electron transitions
We report on the identification of a two-electron transition for the shallow donor silicon in homoepitaxial AlN. One c-oriented sample was analyzed by low temperature PL spectroscopy on multiple excitation spots. We find a unique correlation of one single emission band, 76.6 meV below the free excitonic emission with the luminescence of excitons bound to neutral silicon proving the identity as a two-electron transition. The assignment is confirmed by temperature dependent PL investigations. We find a donor ionization energy of 63.5 +/- 1.5 meV for silicon in AlN. Beyond, based on our experimental results, we comment on the discussion about the role of silicon impurities in wurtzite AlN supporting the approach that silicon forms a DX center with the DX-ground state lying closely below the neutral donor state.
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Neuschl, B.; Thonke, K.; Feneberg, M.; Goldhahn, R.; Wunderer, T.; Yang, Z.; Johnson, N. M.; Xie, J.; Mita, S.; Rice, A.; Collazo, R.; Sitar, Z. Direct determination of the silicon donor ionization energy in homoepitaxial AlN from photoluminescence two-electron transitions. Applied Physics Letters. 2013 September 16; 103; 122105.
Copyright © American Institute of Physics, 2013. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Applied Physics Letters and may be found at http://link.aip.org/link/doi/10.1063/1.4821183.