Optical Transitions in Cubic GaN Grown by Metalorganic Chemical Vapor Deposition on GaAs (100) Substrate
Chin. Phys. Lett. 2000, 17 (8):
Photoluminescence measurements have been performed on cubic GaN films with carrier concentration as low as 3x1013 cm-3. From the temperature and excitation intensity dependence, the emission lines at 3.268, 3.150 and 3.081 eV were assigned to the excitonic, donor-acceptor pair, and free-to-acceptor transitions, respectively. Additionallx we observed two additional emission lines at 2.926 and 2.821 eV, and suggested that they belong to donor-acceptor pair transitions. Furthermore, from the temperature dependence of integral intensities, we confirmed that three donor-acceptor pair transitions (3.150, 2.926, and 2.821 eV) are from a common shallow donor to three different acceptors. The excitonic emission at 3.216 eV has a full-width-at-half-maximum value of 41 meV at room temperature, which indicates a good optical quality of our sample.