Analysis of local minority carrier diffusion lengths in liquid phase crystallized silicon thin-film solar cells

We developed a method to quantify the local minority carrier diffusion lengths in interdigitated back-contact solar cells having a 10 μm thick liquid phase crystallized (LPC) Si absorber by light-beam induced current (LBIC) measurements. The method is verified by 2-D simulations of the LBIC signals using ASPIN3. The effective minority carrier diffusion lengths determined this way range between 33–44 μm inside a grain, which proves that advanced cell concepts like an IBC system are well suited for the LPC absorbers. Furthermore, the method has the potential to help improving the optimization of contact system geometries and it may be used to understand the influences of different grain orientations and improve the LPC-Si absorber fabrication process.