Novel methods of p-type activation in Mg-doped GaN

We have developed two methods for the p-type activation of Mg-doped GaN; a low-temperature long-time annealing method and a RF input activation method. In the low-temperature long-time annealing method, hole concentration increased in proportion to the square root of annealing time. It took similar to 80h to obtain hole concentrations of similar to 10(18) cm(-3) at 385 degreesC annealed in air. In the RF input activation method, hole concentration increased with the product of RF input time and amplitude of the RF electric field. It took similar to 70 s to get hole concentrations of similar to 10(18) cm(-3) at a RF electric field of similar to 21 kV/cm. No specific difference was observed for the optical and electrical properties as compared to those of thermally activated samples annealed between 475 degreesC and 800 degreesC in a N-2 atmosphere. The photoluminescence (PL) intensity was found to decrease with increasing hole concentration in all activation methods. Nonradiative recombination process is thought to become dominant at hole concentrations over similar to2 x 10(16) cm(-3) independent of the activation method.