Tunable band gaps in bilayer transition-metal dichalcogenides

Stark Effect Spectroscopy of Mono- and Few-Layer MoS2

“…Moreover, spectral tuning of the energy gap using vertically applied electric fields has been theoretically proposed for bilayer MoS2 crystals. [13][14][15][16] In this letter, we report on electrical control of the A-exciton emission energy of mono-and fewlayer MoS2 crystals using the DC Stark effect. Hereby, we employ a lithographically defined microcapacitor device which facilitates optical access to atomically thin MoS2 crystals whilst the electric field perpendicular to the basal plane of the crystal is tuned.…”

Electron transport in MoWSeS monolayers in the presence of an external electric field

“…[12][13][14][15][16] By means of further theoretical studies it has been reported that applying an external electric field to a rippled MoS 2 monolayer 17 or an armchair MoS 2 nanoribbon 18 reduces the band gap and causes severe changes in the electronic structure. Ramasubramaniam and co-workers 19 have studied the effect of the perpendicular external electric field applied to TX 2 bilayers. Their results, obtained via first principles based plane wave calculations, indicate that the band gap decreases linearly with the external electric field, resulting in a semiconductor-metal transition in the range of relatively small electric field of 200-300 mV A −1 .…”

Two-dimensional inorganic analogues of graphene: transition metal dichalcogenides

“…Besides the number of layers, the band gap in group VI TMDCs can be tuned by application of electric field or a mechanical strain. For instance, the indirect-band gap of bilayer TMDCs can be driven to zero at an electric field of 2-3 Vnm −1 applied perpendicular to the layers, allowing for larger band gap tuneability than that in graphene [65]. Under strain, the band gap of mono-and bi-layer MoS 2 decreases and the material undergoes an insulator-to-metal transition [66][67][68][69].…”