Theory of photoconductivity in amorphous semiconductors containing relatively narrow trap bands

Abstract

For a constant rate G of generation of electron-hole pairs, lg Jph (Jph is the photocurrent) increases as T-1 at high temperatures and reaches a maximum value of Jm at T=Tm. Thereafter, lg Jph decreases as T-1 with further decrease in temperature and finally, at low temperatures, Jph becomes independent of temperature. The lg Jph against T-1 characteristics scale to high current and Tm increases with increasing G. At constant temperature, say T1, Jph is a linear function of G up to the value of Jm corresponding to T1, and in this range the curves scale to higher currents levels with decreasing T. For Jph>Jm, Jph increases as G12/, and in this range the curves scale to high current levels with increasing T. At very high light levels or at low temperatures, corresponding to the case where Jph is temperature independent, the Jph against G curves for different constant temperatures all merge and Jph is found to be linearly proportional to G.