Optical studies of bulk and homoepitaxial films of III–V nitride semiconductors

Optical characteristics of GaN single crystals grown by the HVPE: Effects of thermal annealing and N2 plasma treatment

“…4. In general, room-temperature PL spectra of GaN crystal are dominated by the band-edge transition at 3.39 eV [15]. From the relative intensity of the band-egde PL peaks, it is seen that the annealing in N 2 at 900 1C showed a maximum enhancement of the PL intensity over the aspolished GaN.…”

Optical properties of bulk GaN crystals grown from solution at moderate pressure and temperature

“…This spectrum shows a dominant peak associated with annihilation of free and bound excitons at 3.47 eV, commonly known as near bandedge emission (NBE) [17] with its phonon replica (1LO-NBE) at 3.37 eV. The intense broad band centered near 3.15 eV has been assigned to recombination processes involving electrons in the shallow neutral donors with holes in the shallow neutral acceptors [18]. This band, called the shallow donor/shallow acceptor pair (DAP) band, has a zero phonon line at 3.26 eV, and phonon replicas at from the valance band B (FX B ) at 3.485 eV.…”

Growth of GaN on Porous SiC by Molecular Beam Epitaxy

“…The two B 1 are silent modes, or Raman inactive, but all the six allowed first order phonons have been observed in thin films [22]. These phonons have also been observed in thick and high quality freestanding HVPE GaN substrates and their energy have been used for estimate the biaxial stress in our samples [23].…”