To support the hypothesis of Auger processes driving the emission, we systematically studied the excitation wavelength dependence of the PL. Using a supercontinuum laser coupled to a tunable monochromator enabled us to achieve a finer resolution in λ ex than previously reported in the literature, allowing us to trace the excitation pathways in the material. Through this approach, we are able to show that the PL arises from pure interband absorption followed by pure intraband emission and to thereby substantiate our hypothesis that the observed emission corresponds to Auger-excited intraband PL.