Synthesis of vertically aligned wafer-scale tantalum disulfide using high-Ar/HS ratio plasma.

Nanostructural modification of two-dimensional (2D) materials has attracted significant attention for enhancing hydrogen evolution reaction (HER) activity. In this study, the nanostructure of TaSfilms was controlled by controlling the Ar/HS gas ratio used in plasma-enhanced chemical vapor deposition (PECVD). At a high Ar/HS gas ratio, vertically aligned TaS(V-TaS) films were formed over a large-area (4 in) at a temperature of 250 °C, which, to the best of our knowledge, is the lowest temperature reported for PECVD. Furthermore, the plasma species formed in the injected gas at various Ar/HS gas ratios were analyzed using optical emission spectroscopy to determine the synthesis mechanism. In addition, the 4 in wafer-scale V-TaSwas analyzed by x-ray photoelectron spectroscopy, transmission electron microscopy, and atomic force microscopy, and the HER performance of the as-synthesized TaSfabricated with various Ar/HS ratios was measured. The results revealed that, depending on the film structure of TaS, the HER performance can be enhanced owing to its structural advantage. Furthermore, the excellent stability and robustness of V-TaSwas confirmed by conducting 1000 HER cycles and post-HER material characterization. This study provides important insights into the plasma-assisted nanostructural modification of 2D materials for application as enhanced electrocatalysts.