A study was made of twin emission peaks observed from single iso-electronic traps formed by N pairs in N δ-doped GaAs by means of high-energy resolution micro-photoluminescence spectroscopy. The twin photoluminescence peaks exhibited almost the same intensity, with narrow linewidths of 20 to 50μeV, which were considerably smaller than those ever reported for iso-electronic traps in GaAs:N. The higher and lower energy luminescence transitions were linearly polarized in the [1¯10] and [110] directions, respectively, indicating that the two exciton states had completely orthogonal relationships to each other. The fact that any pair of the twin photoluminescence peaks had the same polarization properties suggested that the splitting was due to the anisotropy between [1¯10] and [110] directions in the host crystal and was possibly explained by the strain anisotropy in the sample.

Twin Photoluminescence Peaks from Single Isoelectronic Traps in Nitrogen δ-Doped GaAs. Y.Endo, Y.Hijikata, H.Yaguchi, S.Yoshida, M.Yoshita, H.Akiyama, F.Nakajima, R.Katayama, K.Onabe: Physica E, 2008, 40[6], 2110-2