Magneto-photoluminescence of AlGaN/GaN quantum wells

The magneto-luminescence of GaN/AlGaN quantum wells in fields up to 52 T sh ows a field dependence that is strongly dependent on the well width. Strong redshifts are seen for the narrowest wells that are attributed to a Zeeman splitting. This is unexpected, since in bulk GaN epilayers the electron an d hole y-factors of the lowest valence band cancel each other almost exactl y. Therefore, we attribute this splitting to a reordering of the valence ba nd due to the different band offsets caused by the strain and the aluminium component in the AlGaN barriers. The field dependence also gives informati on on the size of the exciton that has been converted into values for the e xciton binding energy, and these values agree reasonably well with a theory that includes the presence of the electric field. (C) 2001 Elsevier Scienc e B.V. All rights reserved.