| 초록 |
The Cu2ZnSn(S,Se)4 Solar cells has been attracting great attention, because its absorber consists of earth-abundant and nontoxic elements. CZTSSe solar cells however, perform poorly compared to counterparts such as Cu(In,Ga)(S,Se)2 (CIGS) solar cells and CdTe solar cells, due to high open-circuit voltage (Voc) deficit. The high Voc deficit in CZTSSe solar cells may be caused by band tailing effect, point defects, surface recombination, and etc. In particular, fabrication of absorber using PVD can easily lead to poor surface morphology such as pin-hole and voids. If the annealing temperature is too low, the grains size is small, and if the annealing temperature is too high, both Sn loss and secondary phase which known as the recombination center for mobile charge carriers occur. To overcome this problem, during chamber RTA process, slightly different working temperatures are applied in order to form large and uniform CZTSSe grains. It is also aims to suppress creation of the secondary phase. The CZTSSe films are prepared by sputtering and post-annealing process, and analyzed by X-ray diffraction, Raman spectroscopy, Incident photon-electron conversion efficiency, and Scanning electron microscopy. |
