Measurements of photoluminescence and its dependence on hydrostatic pressure are performed on a set of InN/nGaN superlattices with one InN monolayer, and with different numbers of GaN monolayers (n from 1 to 40). The emission energies, E_PL, measured at ambient pressure, are close to the value of the band gap, E_g, in bulk GaN, in agreement with other experimental findings. The pressure dependence of the emission energies, dE_PL/dp, however, resembles that of the InN energy gap. Further, the magnitudes of both E_PL and dE_PL/dp are significantly higher than those obtained from abinitio calculations for 1InN/nGaN superlattices. Some causes of these discrepancies are suggested...Detailed analysis of the electronic band structure of 1InN/5GaN superlattice is performed showing that the built-in electric field plays an important role in the mInN/nGaN structures. It strongly influences the valence- and conduction-band profiles and thus determines the effective band gap.

Date Published: 27 March 2013
PDF: 7 pages
Proc. SPIE 8625, Gallium Nitride Materials and Devices VIII, 86250J (27 March 2013); doi: 10.1117/12.2004313

Published in SPIE Proceedings Vol. 8625:
Gallium Nitride Materials and Devices VIII
Jen-Inn Chyi; Yasushi Nanishi; Hadis Morkoç; Joachim Piprek; Euijoon Yoon; Hiroshi Fujioka, Editor(s)