Temperature-related exciton features on the Ga/N-Faces of a free-standing HVPE GaN

<span lang="EN-US" new="" style="font-family: ;" times=""><font color="#000000">An apparently different effect of excitonic luminescence has been observed on the Ga-/N-faces of a free-standing HVPE GaN. The neutral donor-bound exciton (D-2(0) X) emission of the N-face is only dominant at lower temperature as compared with that of the Ga-face. Moreover, the temperature-related ratio of the peak intensity of D-2(0) X to X-A(n=1) (a free exciton) is found to be about 2.8, which is in coincidence with the ratio of the average dislocation density of the N-face to the Ga-face confirmed by Cathodoluminiscence images. These details could provide useful information for the design of GaN-based and related devices. (C) 2014 Optical Society of America</font>