Depth profiling of Cu(In,Ga)Se2 thin films grown at low temperatures

In order to understand the effect of the process temperature on the growth of Cu(In,Ga)Se2 (CIGSe) thin films via the 3-stage co-evaporation process, absorber layers have been fabricated on glass using a set of different maximum process temperatures in the nominal temperature range between 330 and 525 °C. Using energy dispersive X-ray analysis, depth profiles could be recorded on cross-sections of finished devices and were correlated to the device performance. The effect of the process temperature on the gallium gradient in the CIGSe layer is evident in the gallium distribution across the depth of the device.