Temperature dependence of photoluminescence from AIN/GaN-thin nanowires

摘要

Well vertically aligned AIN/GaN Nanowires (NWs) with average diameter and length of 25 and 200 nm, respectively, were grown by plasma-assisted molecular beam epitaxy (PA-MBE) on Si (111) substrates. The photoluminescence (PL) spectra of AIN/GaN NWs show strong emission bands around 3.41 and 3.1 eV at low temperatures in addition to the neutral donor-bound excitons (D~0X_A). The temperature dependence of the PL peaks is presented and discussed considering the surface effects and structural defects created in GaN due to the mismatch between the different lattice constants of GaN and AlN. The strong emission band, with an energy lower than the widely reported band edge of GaN, is dominant at temperatures higher than 50 K which enhance the application of AIN/GaN in nanophotonic devices working at room temperature.