Optical absorption spectra were measured for plastically deformed GaN to investigate effects of dislocations. The interband absorption edge was observed to shift noticeably to lower photon energy by deformation, which was analyzed based on a model of the Franz-Keldysh effect by the electric fields associated with charged dislocations. This model satisfactorily reproduced the observed absorption spectra. In a lower energy region, a decrease in free-carrier absorption by deformation was observed, which was partly attributable to the decrease in carrier concentration by carrier trapping at dislocation states.

Dislocation-Related Optical Absorption in Plastically Deformed GaN. H.Hasegawa, Y.Kamimura, K.Edagawa, I.Yonenaga: Journal of Applied Physics, 2007, 102[2], 026103