Lifetime Characterization of Mc:Si Bricks by Upgraded µ-PCD Technique

A very efficient way is introduced to improve the application of the conventional µ-PCD lifetime mapping technique to bulk photovoltaic grade Si materials (ingots, blocks). The shape of the recorded photoconductance decay curves are strongly impacted by the properties of the laser applied for the electron-hole pair generation. Replacing the original laser configuration to an optimized setup, the impact of the surface recombination can be reduced resulting in significantly longer measurable decay times. It makes possible the better carrier lifetime characterization of the good quality part of the Si bricks. Additionally, unlike similar techniques the suggested realization of µ-PCD gives a relatively homogenous injection level of the measurement along the entire Si bricks. Experimental and simulation results are in excellent agreement, and confirm the enhanced applicability of the upgraded µ-PCD technique.