Characterization of TCO deposition for CIGS solar cells

Transparent conducting ZnO:Al (AZO) thin films were deposited by using radio frequency (RF) magnetron sputtering system and were analyzed with regards to their potential application as a window layer for CIGS solar cells. Their properties were measured in-situ and ex-situ by real time spectroscopic ellipsometry (RTSE) and were correlated with ex-situ characterization, such as AFM, XRD, and T&R measurements. As the deposition power was increased, an increase in the conductivity (via an increase by the contribution of the Drude oscillator), a reduction of the transmittance in the IR and an increase in the grain size was observed by RTSE, while the growth mechanism remained the same for all powers.