Impacts of intrinsic defects on luminescence properties of CuAlS_2

摘要

The authors report on Raman scattering of CuAlS_2 in order to study the influences of intrinsic defects on luminescence properties. The A_1 mode is dominated in stoichiometric samples, whereas sulfur-poor conditions prepared at high temperatures (≥ 800℃) cause defect-specific shift and broadening. They also find that additional mode (at 330 cm~(-1)) caused by antisite defects is resonated at 2.16 eV excitation, in accordance with visible luminescence attributed to donor-acceptor pair (DAP) emission in photoluminescence. These results suggest that the DAP emissions may be caused by the defect complexes such as Al_(Cu)-V_(Cu) and V_S-V_(Cu), which reduces ultraviolet excitonic emission in this system.