Analysis of polarization anisotropy along the c axis in the photoluminescence of wurtzite GaN

The polarization of photoluminescence (PL) was investigated on (<1(1)over bar 00>) GaN grown by metalorganic vapor phase epitaxy. We found that the PL intensity and wavelength have polarization dependence parallel and perpendicular to the c axis, We quantitatively analyzed the dependence and found that, since the crystal field of wurtzite GaN along the c axis is strong enough to fix the \z] axis of p functions at the c axis, the difference in symmetry between three valence bands appears as the polarization anisotropy in radiative emission, even in bulk GaN. (C) 1997 American Institute of Physics.