  The millimeter sized monolayer and bilayer 2H-MoTe2 single crystal samples
are prepared by a new mechanical exfoliation method. Based on such high-quality
samples, we report the first direct electronic structure study on them, using
standard high resolution angle-resolved photoemission spectroscopy (ARPES). A
direct band gap of 0.924eV is found at K in the rubidium-doped monolayer MoTe2.
Similar valence band alignment is also observed in bilayer MoTe2,supporting an
assumption of a analogous direct gap semiconductor on it. Our measurements
indicate a rather large band splitting of 212meV at the valence band maximum
(VBM) in monolayer MoTe2, and the splitting is systematically enlarged with
layer stacking, from monolayer to bilayer and to bulk. Meanwhile, our PBE band
calculation on these materials show excellent agreement with ARPES results.
Some fundamental electronic parameters are derived from the experimental and
calculated electronic structures. Our findings lay a foundation for further
application-related study on monolayer and bilayer MoTe2.
