The hole concentration of CaCuP films rises very slowly with temperature (Figure ). This behavior is typical of a degenerately doped semiconductor, and is in excellent agreement with defect calculations, which predict degenerate semiconducting behaviour through acceptor levels at or below the valence band maximum, shown in the transition level diagram for the most ptype growth conditions (Figure ). On the other hand, the hole mobility µ(T ) decreases with temperature. This trend can be de- scribed by considering two parallel scattering channels, so that