LAUSR

The impact of carbon doping on the background carrier conduction in GaN has been investigated. It is found that the incorporation of carbon can effectively suppress the n-type background carrier concentration as expected. Moreover, from the fitting of the temperature-dependent carrier concentration and mobility, it is observed that high nitrogen–vacancy (VN) dominates the background carrier at room temperature which consequently results in n-type conduction. The doping agent (carbon atom) occupies the nitrogen site of GaN and forms CN deep acceptor as revealed from photoluminescence. Besides, a relatively low hole concentration is ionized at room temperature which was insufficient for the compensation of n-type background carriers. Therefore, we concluded that this background carrier concentration can be suppressed by carbon doping, which substitutes the N site of GaN and finally decreases the VN.