Fig. 1: Phase-selective growth of H-phase CrSe2 monolayers induced by the in-plane template of MoSe2 nanoribbons.
From: Phase-selective in-plane heteroepitaxial growth of H-phase CrSe2
a Schematic illustration of the epitaxial growth of T-phase and H-phase CrSe2 at different growth conditions. The highly oriented pyrolytic graphite (HOPG) is chosen as the epitaxial substrate. In the atomic model of the lateral heterostructure, the purple area represents the MoSe2 nanoribbon, and the yellow areas represent the CrSe2 segments. b,c The ball-and-stick models and electron energy diagrams for the T-phase CrSe2 and H-phase CrSe2, respectively. In the electron energy diagrams, \({d}_{{x}^{2}-{y}^{2},{{z}}^{2}}\), \({d}_{{xy},{yz},{xz}}\), \({d}_{{xz},{yz}}\), \({d}_{{x}^{2}-{y}^{2},{yz}}\) and \({d}_{{z}^{2}}\) represent the different d orbitals that are located within the bandgap between the bonding (σ) and antibonding (σ*) states, and EF indicates the Fermi level. d Scanning tunneling microscopy (STM) topographic image of an isolated 1T-CrSe2 island on a HOPG substrate (sample voltage VS = − 2.0 V, tunneling current It = 10 pA). The inset shows the height profile across the CrSe2 island. e STM topography of MoSe2 nanoribbons grown at 550 °C (VS = − 2.0 V, It = 10 pA). f Large-scale STM image of lateral heterostructures with H-phsae CrSe2 segments seamlessly connnected to MoSe2 nanoribbons (VS = 1.3 V, It = 10 pA). g Differential conductance (dI/dV) spectrum measured on T-phase CrSe2. The vertical dashed line at the 0 V sample voltage indicates the Fermi level. h X-ray photoelectron spectroscopy (XPS) characterization of the Cr 2p and Se 3d peaks in T- and H-phase CrSe2 monolayers. i Differential conductance (dI/dV) spectra taken at the same bias voltage and different tunneling currents on the CrSe2 regions of lateral heterostructures. The bandgap is marked by the vertical dashed lines at the position of the valence band maximum and conduction band minimum, respectively.
