1/f noise as a reliability estimation for solar cells

The 1/f noise from a forward biased dark solar cell is a non-destructive reliability estimation. The experimentally observed 1/f noise is compared with Kleinpenning's one-dimensional calculations for p-n diodes. At medium and low currents the 1/f noise of n⁺-p solar cells is about 50 times as large as predicted. Such deviations can be caused by non-uniformities in the large junction area. Local areas with lower built-in potentials at the junction lead to hot spots and reduced reliability. At large currents, reliability problems due to possible poor contacts can be studied from the proportionality between the noise and the square of the current.