METHOD FOR DETERMINING THE EFFECTIVE LIFETIME OF NONEQUILIBRIUM CHARGE CARRIERS IN P(N) LAYERS OF LOCAL SECTIONS OF N-P(N)-P TYPE SILICON SOLAR CELLS Russian patent published in 2023 - IPC H01L21/66 

FIELD: testing equipment.

SUBSTANCE: method is designed to determine the effective lifetime (τ_eff) of nonequilibrium charge carriers in local sections of solar cells (SC) and subsequent assessment of its quality, as well as the detection of its defects with a view to their subsequent elimination. The method is based on illuminating local sections of the SC with a beam of light modulated in intensity and measuring alternating voltage directly from the contacts of the SC or from a microwave detector. The alternating voltage at the microwave detector is determined by the modulation of the absorption of the microwave by the illuminated section of the SC. A distinctive feature of the method is that in order to increase the accuracy of determining the τ_eff of the local sections of the SC by eliminating the shunting of the illuminated section by the surrounding unlit sections, a constant locking voltage is applied to the SC. Moreover, to avoid the shunting of the illuminated section at the light modulation frequency by the source of this voltage, a resistor and/or inductance are connected between the source of this voltage and the contacts of the SC, the total differential resistance of which is significantly greater than the internal resistance of the illuminated section.

EFFECT: excluding at the frequency of light modulation the effect of the shunting action of currents along the front and back sides of the SC along the p⁺- and n⁺- layers and the contacts covering them by supplying a constant voltage to the contacts of the SC sufficient to lock the SC during the entire modulation period, as a result, the possibility of extraction of the NCC of the illuminated SC section and their subsequent injection into the surrounding unlit sections of the SC.

6 cl, 6 dwg, 1 tbl