Optical characterization of nitrogen (N)-doped GaAs was performed by low-temperature photoluminescence (PL) measurements. N doping in GaAs was successfully made by irradiating low-energy (100 eV) N+ ion beam during the growth of GaAs using the combined ion beam and molecular beam epitaxy (CIBMBE) system. For the sample with N+ ion beam current density (IN) of 3 nA/cm2, which correspond to N concentration ([N]) of ∼ 5 × 1017 cm-3, two sharp PL emissions were observed at 1.508 eV (X1) and 1.495 eV (X2). For the sample with IN of 75 nA/cm2 ([N]≈ 1 × 1019 cm-3), several novel PL emissions tentatively labeled by Yj (j = 1, ..., 8) were observed in the energy range of 1.491-1.449 eV by furnace annealing at 750°C for 20 min. Photoluminescence excitation measurements indicated that X1 is correlated with the PL emission at 1.514 eV. Since the energy separation between individual Yj (j = 1, ..., 8) and X2 is almost linear to r-3 k, where rk is the distance between nitrogen-nitrogen (NN) pairs, we ascribed X2 and Yj as the radiative transition of excitons bound to isolated N and that to N-N pairs, respectively.
|ジャーナル||Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms|
|出版ステータス||Published - 1997 5月|
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