Formation of copper tin sulfide films by pulsed laser deposition at 248 and 355 nm

Abstract

The influence of the laser wavelength on the deposition of copper tin sulfide (CTS) and SnS-rich CTS with a 248-nm KrF excimer laser (pulse length τ=20 ns) and a 355-nm frequency-tripled Nd:YAG laser (τ=6 ns) was investigated. A comparative study of the two UV wavelengths shows that the film growth rate per pulse of CTS was three to four times lower with the 248 nm laser than the 355 nm laser. SnSrich CTS is more efficiently ablated than pure CTS. Films deposited at high fluence have sub-micron and micrometer size droplets, and their size and area density do not vary significantly from 248 to 355 nm deposition. Irradiation at low fluence resulted in a non-stoichiometric material transfer with significant Cu-deficiency in the as-deposited films. We discuss the transition from a non-stoichiometric material transfer at low fluence to a nearly stoichiometric ablation at high fluence based on a transition from a dominant evaporation regime to an ablation regime.

Ultra-thin Cu2ZnSnS4 solar cell by pulsed laser deposition

“…5. The as-deposited films are amorphous and, in particular, (b) and (c) are studded with micron-sized droplets which are primarily a mixture of copper and sulfur [28]. From Figures 4 and 5 it is clear that, by increasing the laser fluence, both the copper content in the films and the amount of Cu-S droplets are increasing.…”

Temperature dependent photoreflectance study of Cu2SnS3 thin films produced by pulsed laser deposition

“…The fluence had been adjusted to yield the correct Cu:Sn ratio in the films. 21 The target was a multiphase sintered pellet made from binary sulfides mixed for an average target composition of 2Cu:Sn:3S (PVD products; manufactured by Testbourne, Ltd.). The target sintering temperature was about 750 C, and the resulting pellet had microdomains of copper sulfides, tin sulfides, and copper tin sulfides.…”

Effect of Li Doping on Cu2SnS3/n‐Si Heterojunction Solar Cells: Experiments and Simulation

“…The Cu/Sn ratio slightly decreases after the sulfurization process; this is due to the possible diffusion of Sn atoms to the surface of the thin film during the annealing process that increased its concentration and decreased the Cu/Sn ratio from 2.39 to 2.36. [ 68–71 ]…”

“…[67] This was caused by the high evaporation pressure of these materials. [68,69] During the sulfurization process, the incorporation of S powder [67] into CTS thin films increases the ratio of S/(Cu + Sn) from 0.63 to 0.80 due to the high S pressure in annealing treatment. The Cu/Sn ratio slightly decreases after the sulfurization process; this is due to the possible diffusion of Sn atoms to the surface of the thin film during the annealing process that increased its concentration and decreased the Cu/Sn ratio from 2.39 to 2.36.…”