Figure 5: Gate-Dependent HER.

(a) Schematic of the gate-dependent electrochemical device, with the SiO₂ layer acting as the gate. (b) Optical micrograph of gold contacts and 2H-MoS₂ single layer flake. The edges of the MoS₂ flake masked with PMMA are outlined by the black dotted line, the exposed window can be seen as the darker region. Scale bar, 10 μm (c) Linear voltammograms from the gate-dependent HER measurements on the single MoS₂ flake device. The black curve is the activity of the flake with no applied voltage. The green and red curves show the improvement in electrocatalytic activity after applying a positive gate voltage of 10 and 20 V, respectively.