SiOxNy back-contact barriers for CZTSe thin-film solar cells.

The formation of molybdenum diselenide (MoSe2) is widely observed at the back-contact interface for copper zinc tin selenide (CZTSe) thin-film solar cells. Depending on individual selenium (Se) supply and thermal conditions for forming CZTSe absorbers on molybdenum (Mo) substrates, the thickness of MoSe2 can vary from a few hundreds of nanometers up to ≈ 1 μm, which is comparable to the commonly adopted thickness of 1 ~ 1.5 μm for CZTSe absorbers.

The effect of excess selenium on the opto-electronic properties of CuZnSnSe prepared from Cu-Sn alloy precursors.

For the fabrication of a kesterite-type CZTSe absorber material, stacked elemental-alloy layers (SEAL) precursor consisting of Cu-Sn alloy and elemental Zn layers offer the possibility of enhanced process control due to their advantages such as improvement of material homogeneity and suppression of the commonly observed Sn loss. In this study, the impact of selenium amounts during the annealing of a SEAL-type precursor with the configuration of Zn/Cu-Sn/Zn was demonstrated. The obtained results demonstrate how the selenium amount can indirectly be used to influence the absorber composition in the described annealing process and its direct impact on the opto-electronic properties of solar cells.

Growth of large sized two-dimensional MoS flakes in aqueous solution.

A large lateral size and low dimensions are prerequisites for next generation electronics. Since the first single layer MoS transistor reported by Kis's group in 2011, layered transition metal dichalcogenides (TMDs) have been demonstrated to be the ideal candidate for next generation electronics. However, the development of large scale and low cost growth techniques is a crucial step towards TMDs' inclusion in modern electronics and photoelectronics.