While today's GaxIn1−xN-based blue-light-emitting quantum wells exhibit internal

quantum efficiencies in excess of 60%, ultraviolet structures at wavelengths shorter

than 360nm still were limited to efficiencies of a few percent. Recently, it was

demonstrated that antilocalization of charge carriers due to energy barriers arising

from sidewall quantum wells in V-shaped pits decorating dislocations was a key to

understanding the high efficiency of GaxIn1−xN-based quantum wells. Here it was

shown that the unexpected presence of V-shaped pits in GaN/AlxGa1−xN quantum

wells leads to a dramatically increased internal efficiency of about 30%. In

contrast, the efficiency of quantum wells with flat interfaces in the vicinity of

dislocations remains very low.

Dislocation Screening and Strongly Increased Internal Quantum Efficiency in

Heteroepitaxial GaN/AlxGa1−XN Ultraviolet-Emitting Quantum Wells.

D.Fuhrmann, T.Retzlaff, M.Greve, L.Hoffmann, H.Bremers, U.Rossow,

A.Hangleiter, P.Hinze, G.Ade: Physical Review B, 2009, 79[7], 073303