Rapid thermal annealing effect on Cu(In, Ga)Se₂ solar cells

The paper studies the rapid thermal annealing(RTA) effect on Cu(In, Ga)Se2 (CIGS) solar cells at different annealing temperatures by photoluminescence(PL). Continuous RTA was applied to CIGS solar cells to study annealing effect on film defects. Seven peaks exist in CIGS PL spectra: two in visible light region, the others in infrared region. When the temperature is relatively low, RTA treatment can improve the film quality because of the decrease of defects and the increase of carriers. High temperature RTA treatment will lead to elements diffusion between layers and change of stoichiometric ratio, increasing interface states and decreasing the bandgap of absorber layer, and thus destroy the device structures.