Pressure and Time‐Resolved Photoluminescence Studies of Mg‐Doped and Undoped GaN

Abstract

Abstract Pressure and time‐resolved photoluminescence (PL) experiments were performed on undoped and Mgdoped GaN homoepitaxial layers. The pressure coefficients of the following PL lines were determined: (i) exciton bound to a neutral donor (3.472 eV), (ii) exciton bound to a neutral acceptor (3.463 eV), (iii) line centered at about 3.27 eV and its two LO (92 meV) phonon replicas. In the time‐resolved measurements, we observed that the latter PL line corresponds to a slow process (delay time is in the millisecond range). This observation strongly supports the conclusion that donor‐acceptor pairs are responsible for this radiative transition. Identification of the radiative centers and a new explanation of the radiative mechanisms (including optically active E 1 2 phonons) are proposed.