Figure 14

(a) ²³Na/⁷⁸Se SIMS depth profiles of a CIGS film obtained with intentional 0.6 at. % Na²⁸ (black curve) and of part of the same film re-annealed under Se flux at 500 °C for seven minutes (red curve). The sputtering time scales are shifted linearly for comparison purposes (the ⁹⁸Mo signals of the back contact are made to overlap). The corresponding SEM cross sectional images of the films are shown respectively in (b) and (c), as complete solar cell devices.