Phase shift analysis of modulated photocurrent: Determination of the energy scale

For the determination of the density of states in the mobility gap of amorphous semiconductors using the phase shift analysis of modulated photocurrent, this paper suggests that making use of the magnitude of the induced photocurrent helps to remove arbitrariness in the energy scale. The working equations for the density of states and the corresponding energy position are expressed in terms of the intensity of the photocurrent. A simulation is made for a specific distribution, to investigate the validity of the procedure. The results show that the profile of the energetic distribution of localized states and the exact energy position of each state are consistent with the original distribution considered.