cm 3 in as-grown, nominally-undoped polycrystalline t-Se samples, using capacitance-voltage (CV) techniques. In contrast, Todorov et al. reported a much lower hole concentration of 3 ⇥ 10 12 cm 3 in their polycrystalline t-Se samples using AC Hall measurements. The variance in reported values, discrepancies between measured doping and carrier densities, and atomistic origins of hole doping in t-Se -whether intrinsic/extrinsic defects, interfaces or otherwise, have not yet been resolved.