TY  - JOUR
AU  - Schneemann, Matthias
AU  - Kirchartz, Thomas
AU  - Carius, Reinhard
AU  - Rau, Uwe
TI  - Electric properties and carrier multiplication in breakdown sites in multi-crystalline silicon solar cells
JO  - Journal of applied physics
VL  - 117
IS  - 20
SN  - 1089-7550
CY  - Melville, NY
PB  - American Inst. of Physics
M1  - FZJ-2015-03276
SP  - 205703
PY  - 2015
AB  - This paper studies the effective electrical size and carrier multiplication of breakdown sites in multi-crystalline silicon solar cells. The local series resistance limits the current of each breakdown site and is thereby linearizing the current-voltage characteristic. This fact allows the estimation of the effective electrical diameters to be as low as 100 nm. Using a laser beam induced current (LBIC) measurement with a high spatial resolution, we find carrier multiplication factors on the order of 30 (Zener-type breakdown) and 100 (avalanche breakdown) as new lower limits. Hence, we prove that also the so-called Zener-type breakdown is followed by avalanche multiplication. We explain that previous measurements of the carrier multiplication using thermography yield results higher than unity, only if the spatial defect density is high enough, and the illumination intensity is lower than what was used for the LBIC method. The individual series resistances of the breakdown sites limit the current through these breakdown sites. Therefore, the measured multiplication factors depend on the applied voltage as well as on the injected photocurrent. Both dependencies are successfully simulated using a series-resistance-limited diode model.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000355918300036
DO  - DOI:10.1063/1.4921286
UR  - https://juser.fz-juelich.de/record/200929
ER  -