Spectral response of the photoconductance: a new technique for solar cell characterization

A new technique, the spectral response of the steady-state photoconductance, is proposed for solar cell characterization in research and development. The method is experimentally demonstrated with solar cell precursors having emitters with markedly different levels of surface and bulk recombination losses. A highefficiency solar cell has been investigated, comparing the new spectral response method to the conventional spectral response. The spectral response of the photoconductance has been measured with a contactless quasisteady state photoconductance method (QSSPC) using light of different wavelengths. The measured spectral response of the photoconductance has been compared to PC1D simulations. A good agreement between theory and experiment, and between the two spectral response techniques has been found. The main advantages of the spectral photoconductance technique are that it is fast, contactless, and can be used immediately after junction formation before metallization. These properties make it very appropriate for routine monitoring of the emitter region, including in-line process control.