Figure 1
From: Charge-transfer-based Gas Sensing Using Atomic-layer MoS2
Large-scale synthesis of MoS2.
(a) Schematic of the atomic-layered MoS2. The quasi-2D MoS2 was occupied by one Mo (a trigonal prismatic structure) and two S atoms (hexagonal planes). (b) Image of the as-synthesised MoS2 film on the 2-inch sapphire substrate. The as-synthesised MoS2 film was semi-transparent. (c) Cross-sectional TEM images of the as-grown MoS2 films. The image clearly demonstrates that the synthesised MoS2 films consisted of three layers of MoS2. (d) Raman spectrum of the triple-layered MoS2. The spectrum reveals a strong in-plane vibrational mode for the Mo and S atoms (E2g) and an out-of-plane vibrational mode for the S atoms (A1g). The peak position difference (Δ) between the E2g and A1g bands is approximately 22.9, indicating triple-layered MoS2. (e, f) Raman maps of E2g (blue) and A1g (red), respectively. The Raman mapping area was 50 × 50 μm2 with 0.3 μm steps. The Raman images show the spatial distribution on the surface of the substrates.
