Silicene
[7] Density functional theory (DFT) calculations showed that silicon atoms tend to form such honeycomb structures on silver, and adopt a slight curvature that makes the graphene-like configuration more likely.
However, such a model has been invalidated for Si/Ag(110): the Ag surface displays a missing-row reconstruction upon Si adsorption [8] and the honeycomb structures observed are tip artifacts.
[17] This, however, raises questions of whether silicene can be truly regarded as two-dimensional material at all, due to its strong chemical bonds to the surface alloy.
Its buckled structure gives silicene a tuneable band gap by applying an external electric field.
Silicene on Ag(111) grows on top of a Si/Ag(111) surface alloy, which has been shown by a combination of different measurement techniques.
[17] The surface alloy precedes the growth of silicene, acting both as foundation and as scaffold for the two-dimensional layer.
Power dissipation within traditional metal oxide semiconductor field effect transistors (MOSFETs) generates a bottleneck when dealing with nano-electronics.
Tunnel field-effect transistors (TFETs) may become an alternative to traditional MOSFETs because they can have a smaller subthreshold slope and supply voltage, which reduce power dissipation.
Unlike graphite, which consists of weakly held stacks of graphene layers through dispersion forces, interlayer coupling in silicenes is very strong.
The buckled structure can be flattened by suppressing the PJT distortion by increasing the energy gap between the UMO and OMO.
[18] In addition to its potential compatibility with existing semiconductor techniques, silicene has the advantage that its edges do not exhibit oxygen reactivity.
[23][24][25] Results from scanning tunneling spectroscopy measurements [26] and from angle-resolved photoemission spectroscopy (ARPES) appeared to show that silicene would have similar electronic properties as graphene, namely an electronic dispersion resembling that of relativistic Dirac fermions at the K points of the Brillouin zone,[23] but the interpretation was later disputed and shown to arise due to a substrate band.
[27][28][29][30][31][32][33] A band unfolding technique was used to interpret the ARPES results, revealing the substrate origin of the observed linear dispersion.
The hybridization between Si and Ag results in a metallic surface state, which can gradually decay due to oxygen adsorption.
[40] In 2015, Deji Akinwande, led researchers at the University of Texas, Austin in conjunction with Alessandro Molle's group at CNR, Italy, and collaboration with U.S. Army Research Laboratory and developed a method to stabilize silicene in air and reported a functional silicene field effect transistor device.
Although graphene has a high mobility of electrons, the process of forming a bandgap in the material reduces many of its other electric potentials.
The silicene, Ag, and Al2O3 were stored in a vacuum at room temperature and observed over a tracked period of two months.
The silicene channel on the substrate had a life of two minutes when exposed to air until it lost its signature Raman spectra.
[43] Acoustic phonons describe the synchronous movement of two or more types of atoms from their equilibrium position in a lattice structure.
