摘要
Photoluminescence measurements have been performed on cubic GaN films with carrier concentration as low as 3×10^(13) 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.Additionally,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.
基金
Supported by the National Natural Science Foundation of China under Grant No.69776012.
