Pulsed laser deposition of chalcogenide sulfides from multi-and single-component targets: the non-stoichiometric material transfer

摘要

The mass transfer from target to films is incongruent for chalcogenide sulfides in contrast to the expectations of pulsed laser deposition (PLD) as a stoichiometric film growth process. Films produced from a CZTS (Cu_2ZnSnS_4) multi-component target have no Cu below a fluence threshold of 0.2 J/cm~2, and the Cu content is also very low at low fluence from a single-component target. Above this threshold, the Cu content in the films increases almost linearly up to a value above the stoichiometric value, while the ratio of the concentration of the other metals Zn to Sn (Zn/Sn) remains constant. Films of a similar material CTS (Cu_2SnS_3) have been produced by PLD from a CTS target and exhibits a similar trend in the same fluence region. The results are discussed on the basis of solid-state data and the existing data from the literature.