Fig. 5: Schematic of changes of the VSe2-thickness-dependent optical transition behavior in VBHs after contact with VSe2. | Communications Physics

Fig. 5: Schematic of changes of the VSe2-thickness-dependent optical transition behavior in VBHs after contact with VSe2.

From: Ultrafast interfacial carrier dynamics and persistent topological surface states of Bi2Se3 in heterojunctions with VSe2

Fig. 5

a Schematic of charge transfer and redistribution due to the thermal equilibrium by the junction at VSe2/Bi2Se3 and corresponding charge density near the junction interface. The increase of VSe2 thickness requires a larger amount of electron from Bi2Se3 for Fermi level alignment, leading to an increase of the interfacial dipole strength. Corresponding band diagram for VSe2/Bi2Se3 junctions with thin and thick VSe2 are illustrated with the electron Schottky barrier height (SBH, ФSB) and band offset (\(\triangle\)) as indicated by black and red vertical arrows, respectively. The CB1/CB2, VB, and SS imply the first/second conduction band, valence band, and surface state of Bi2Se3, respectively. The green vertical arrow indicates optical transitions corresponding to probe energies. b VSe2-thickness-dependent band offset (\(\triangle\)) by dipole interactions and c estimated electron ФSB. The expected pinning factor S is listed. The error bars in (b) and (c) come from the standard error for fitted values of Eopt in Fig. 4d.

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