Growth and characterization of isotopic ^natGa¹⁵N by molecular‐beam epitaxy

Abstract

Isotopically enriched gallium nitride films, Ga14N and Ga15N, have been fabricated by molecular‐beam epitaxy to study the effects of nitrogen atomic mass variation on structures and properties of GaN. The phonon frequency shift due to the isotopic substitution was clearly observed using Raman spectroscopy. The lattice constants of Ga15N differed from those of Ga14N; the unit cell volume of Ga15N was approximately 0.06% less than that of Ga14N. Temperature‐dependent photoluminescence measurements revealed that the recombination mechanism in Ga14N and Ga15N was the same in the temperature range of 4‐50 K, and the band gap energy difference was Eg15‐Eg14 = 6.0 ± 0.1 meV. This Eg difference is discussed in terms of volume shrinkage and change in phonon‐electron interaction due to isotopic substitution. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)