Microphotoluminescence studies of Cu 2 ZnSnS 4 polycrystals were performed. At room temperature, two photoluminescence (PL) bands were detected at 1.39 and 1.53 eV and attributed to band-to-tail (BT) and band-to-band (BB) recombination, respectively. At lower temperatures, band-to-impurity recombination always dominates. The results show that the model of heavily doped semiconductors applies to Cu 2 ZnSnS 4 and that, in contrast to the ternary chalcopyrites, the BT recombination in Cu 2 ZnSnS 4 has very low intensity. The laser power dependency of the PL intensity shows that the recombination mechanism of BT and BB bands exhibits an exciton-like behavior.

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