p-type conductivity in cubic (Ga,Mn)N thin films

摘要

The electrical properties of p-type cubic (Ga,Mn)N films are reported. Hole concentrations above 10~(18) cm~(-3) at room temperature are observed. Activated behavior is observed down to 150 K, with an acceptor ionization energy of around 45-60 meV. The dependence of hole concentration and ionization energy on Mn concentration indicates that the shallow acceptor level is not simply due to unintentional codoping. Thermopower measurements on freestanding films, capacitance-voltage profilometry, and the dependence of conductivity on thickness and growth temperature, all show that this is not due to diffusion into the substrate. We therefore associate the p-type conductivity with the presence of the Mn in the cubic GaN films.