Demonstration of efficient p-type doping in Al/sub x/Ga/sub 1-x/N/GaN superlattice structures

Enhanced acceptor activation, reduced acceptor binding energy and enhanced conductivity are demonstrated in Al/sub x/Ga/sub 1-x/N/GaN doped superlattice structures. An acceptor activation energy of 58 meV is demonstrated in an Al/sub 0.20/Ga/sub 0.80/N/GaN superlattice structure with a period of 200 /spl Aring/. This value is significantly lower than the 200 meV activation energy measured in bulk GaN. The dependence of activation energy on the Al content of the superlattice is consistent with that predicted by the theoretical model. The demonstration of improved p-type doping characteristics in GaN is expected to enable the realisation of electronic and optoelectronic devices with improved properties.