Band structure and fundamental optical transitions in wurtzite AlN

The properties of the fundamental optical transitions and band structure in wurtzite (WZ) AlN probed by photoluminescence (PL) spectroscopy measurements. The calculated band structure together with the measured band gap and exciton binding energy were shown. The polarization dependence of the A-exciton emission lines in AlN was measured to confirm the unusual band structure. The origin of the band gap differences in AlN obtained by various measurements was explained through the optical selection rules for near band edge transitions in AlN.