G. Juska et al., NEW FEATURES IN SPACE-CHARGE-LIMITED-PHOTOCURRENT TRANSIENTS, Philosophical magazine. B. Physics of condensed matter. Structural, electronic, optical and magnetic properties, 69(2), 1994, pp. 277-289
We present a theory of space-charge limited photocurrent transients ge
nerated by an instantaneous light pulse, in which the realistic absorp
tion profile of the photogenerated charge is taken into account. This
theory allows us to explain the following features, all observed exper
imentally but not predicted by the standard space-charge-limited-curre
nt theory: (a) the appearance of an initial current spike related to t
he screening of the electric field in the generation region; (b) a str
onger light intensity dependence of the transit time and current cause
d by a decrease in the effective sample thickness; (c) the appearance
of another kink in the space-charge-limited photocurrent transient rel
ated to the full charge reservoir extraction, which may be useful for
investigation of the recombination losses in the generation region of,
for example, hydrogenated amorphous silicon solar cells.