Luminescence properties of multi-layer InGaN quantum dots grown on C- and R-plane sapphire substrates

In this study, we report comparative luminescence properties of multi-layer InGaN quantum dots grown on C- and R-plane sapphire substrates by metal organic chemical vapor deposition (MOCVD). High-density InGaN quantum dots (QDs) are formed on GaN templates by decreasing the growth temperature and increasing the adatom hopping-barrier through surface passivation. Atomic force microscopy (AFM) has been employed to estimate the size and height of these dots. Photoluminescence (PL) spectra recorded from (112¯0) InGaN QDs/(11¯02) sapphire show much stronger emission intensity compared to spectra recorded from (0 0 0 1) InGaN QDs/(0 0 0 1) sapphire. Due to the absence of strong spontaneous polarization and piezoelectric field, such (112¯0) InGaN QDs in the active layers would lead to high efficiency light emitting devices.