Origin of Intrinsic Direct Band Gap of Janus Group‐III Chalcogenide Monolayers

Abstract

InSe based Janus structures has been investigated. The obtained results 6 suggest that the In 2 SeTe Janus structure has an intrinsic direct band gap 7 which is beneficial for optoelectronic applications. The direct band gap nature 8 of In 2 SeTe Janus structure is due to the strong coupling of p z orbitals 9 between the Se and Te sublayers, which emphasizes the importance of the 10 intra-layer interactions. In addition, the effective mass of the holes in In 2 SeTe 11 is one order of magnitude smaller than that of intrinsic InSe monolayer, 12 which makes it a good candidate for p-type semiconductor. The broken 13 mirror symmetry of the Janus structures induces out-of-plane dipolar 14 polarization, yielding additional built-in electric field and offering extra 15 channel to tune its electronic band structure. The electric field has dominated 16 effluences on the charge polarization on anions thus exhibiting stronger band 17 tunability on the valence bands. These results indicate that the preparation of 18 In 2 SeTe Janus structure provides a new way for the future use of two-19 dimensional materials in optoelectronic nanodevices.

The Magnetic Proximity Effect Induced Large Valley Splitting in 2D InSe/FeI2 Heterostructures

“…It shows that the spin-up and spin-down states are well separated, and the Fe spin-down orbitals have negligible hybridization with InSe in valence bands. The VBM of InSe are mainly constructed by the In and Se p z orbitals, which agrees very well with previous reports [ 48 , 49 ]. From Figure 4 , we see that tha I atom is antiferromagnetically coupled with the Fe atom.…”

“…However, there is no band splitting at VBM and the maxima of the sombrero top are degenerated (<2 meV). This sombrero shape band feature is largely originated from the Se p z orbitals [ 48 , 49 ]. Since the Se2 is very close to the I1 atom, the interaction between them will have a stronger effect on the band features.…”

Spin–orbit coupling effect on electronic, optical, and thermoelectric properties of Janus Ga2SSe

“…Excited by the successes in studies of Janus dichalcogenides, Janus monochalcogenides structures, especially Janus structures based on group III-VI compounds, have gained attention recently. 11,18 Wan and co-workers indicated that the Janus In 2 -SeTe exhibits higher carrier mobility that of InSe. 19 Also, strain engineering is one of the good ways to modulate the thermal conductivity of InSe-based Janus.…”

Van der Waals Contact to 2D Semiconductors with a Switchable Electric Dipole: Achieving Both n‐ and p‐Type Ohmic Contacts to Metals with a Wide Range of Work Functions

“…Group III 2 ‐VI 3 monolayers are also proved to be promising photocatalysts for overall water‐splitting with high theoretical solar‐to‐hydrogen efficiency 6. Another class of 2D pS is Janus group‐III chalcogenides (M 2 XY, M = Al, Ga, In; X ≠ Y = S, Se, Te) 18. The Janus M 2 XY monolayers were demonstrated as candidates for nano‐optoelectronics and photocatalytic water splitting 19–23.…”

“…[6] Another class of 2D pS is Janus group-III chalcogenides (M 2 XY, M = Al, Ga, In; X ≠ Y = S, Se, Te). [18] The Janus M 2 XY monolayers were demonstrated as candidates for nano-optoelectronics and photocatalytic water splitting. [19][20][21][22][23] The third class of 2D pS is Janus transition metal dichalcogenides (TMDs).…”