Photoluminescence and reflectance spectroscopy of excitonic transitions in high-quality homoepitaxial GaN films

摘要

We report on highly resolved photoluminescence (PL) and reflectance (RF) spectra of a homoepitaxial GaN layer grown by metal-organic vapor phase epitaxy. This sample exhibits narrow linewidths of several PL emission peaks, down to approximate to 100 mu eV full width at half maximum for some bound exciton transitions. As a consequence, we have detected new PL features as, e.g., a fivefold fine structure of the donor-bound exciton line at approximate to 3.471 eV, and other known PL transitions could be determined with high precision. In RF measurements, the extraordinary quality of the epitaxial layer allowed observation of weakly damped excitonic groundstate transitions and of narrow excited exciton transitions with high signal-to-noise ratio. [S0163-1829(99)14027-X]. [References: 10]