Photoluminescence of cubic InN films on MgO (001) substrates

摘要

We have studied photoluminescence from cubic InN films rown on MgO substrates with a cubic GaN underlayer by N_2 plasma molecular beam epitaxy. A single PL peak was bserved at 0.47 eV. By analyzing the reflectance spectra ofubic InN films, we could derive the refractive index and ex- inction coefficient, and found the band gap energy of cubic InN is 0.48 eV, indicating that the PL peak observed at 0.47 eV is due to the interband transition of cubic InN. The differ-, ence in the PL peak energy between hexagonal and cubic InN is in good agreement with that predicted by ab-initio calculations.