Single contact electron beam induced current technique for solar cell characterization

This paper reports the first demonstration of single contact electron beam induced current (SCEBIC) technique on multicrystalline silicon (mc-Si) solar cells. A lumped single-diode analytical model is also proposed to theoretically explain the SCEBIC phenomenon within solar cells as well as the current transient characteristics of the major model parameters, such as shunt resistance R
_sh
, junction capacitance C
_j
, and parasitic capacitance C
_s
. The accuracy of the analytical model is then verified using PSPICE simulations, which show a close match with the experimental results. It is found that a large value of parasitic capacitance C
_s
is necessary to achieve good SCEBIC signal strength with a relatively low signal-to-noise ratio (SNR), and this is realized experimentally by adopting a metal enclosure in the measurement setup. In addition, the advantage of SCEBIC over conventional double-contact method is also demonstrated by SCEBIC characterization of partially processed solar cells, which clearly illustrates the high degree of flexibility of SCEBIC in solar cell characterization.