In this paper

a method is suggested to analyze the photocapacitance transient which may relate to several deep levels

and the photoionization cross sections

energy positions and concentration of deep levels in 1MeV electron-irradiated GaP :N LED have been measured by photocapacitance technique. And the roles of these deep levels in electron-hole recombination are specified.Photocapacitance experiments showed that certain deep levels in GaP are resulted from electron-irradiation

and that the photocapacitance transient which may include a number of electron or hole emissions from these deep levels is almost always non-exponential. If the electron and hole transitions between deep levels may be neglected

the total transient can be expressed as the sum of the exponential transients corresponding to the deep levels from which electrons or holes are excited to conduction/valence band by light.