Band alignment determination in few-layer exfoliated MoSe2/SiO2 interface using Synchrotron-based photoemission spectroscopy

The ultrathin 2D-layered transition-metal dichalcogenides (TMDs) derived using solution-phase processes have engrossed great attention as an pivitol class of materials for optoelectronics and energy harvesting applications. In this work, we investigated the band alignment in the MoSe2/SiO2 heterointerface synthesized by employing simple, low cost and facile liquid exfoliation method. The high intense crystalline peak of the (002) plane and presence of Raman phononic mode (A(1g) and E-2g(1) modes) pointed toward the formation few monolayer thick MoSe2 nanosheets upon liquid exfoliation. Corroboratively, the electronic structure was verified by XPS (X-ray photoelectron spectroscopy) and VBPES (valence band photoemission spectroscopy). Such that, utilizing both, we have determined a valence and conduction band offset of 4.06 +/- 0.10 eV and 2.60 +/- 0.10 eV at MoSe2/SiO2 heterointerface with a type-I band alignment.