Abstract: A new method based on proportional-integral-derivative (PID) control is proposed to measure photoionization cross sections in GaN materials by analysis of release and recaptures carriers of deep centers by incident light.The measurement results of photoionization cross sections on GaN by this method are consistent with the photoionization spectrum in HEMTs reported by Klein.These results indicate that the photoionization cross section technology based on PID control can measure precisely deep level photoionization cross sections in GaN material.Compared with existing techniques,this method is more operable and applicable.It can serve as a new ‘fingerprint’ analysis method in deep level center detection in GaN .

Key words: photoionization cross section, deep level, PID