Synthesis, physical study and efficient photocatalytic activity of FeTe2

Synthesis and Characterization of Ultrathin FeTe2 Nanocrystals

“…All diffraction peaks can be indexed in the orthorhombic Pnnm (58) space group, with the calculated lattice parameters a = 5.262(2) Å, b = 6.2608(2) Å, and c = 3.871(2) Å. These values correspond well to the reported standard values , with no impurity present.…”

“…Density functional theory found no significant energy difference between the two arrangements . Early studies show that FeTe 2 crystals have an anisotropic antiferromagnetic ground state below about 80 K and a possible ferromagnetic (FM) state below approximately 30 K. − The electronic structure features a reported band gap of 0.35–0.67 eV, as deduced from electrical transport measurements. , FeTe 2 thin films have been found to feature a low thermal conductivity value of 1.20 W m –1 K –1 . Electron-doped marcasite FeTe 2 crystals are a good candidate for thermoelectric applications due to the sharp increase in density of states around the band edges, which favors a large increase in the thermoelectric power factor S 2 σ, where S is the thermopower and σ is the electrical conductivity …”

“… 7 , 9 FeTe 2 thin films have been found to feature a low thermal conductivity value of 1.20 W m –1 K –1 . 10 Electron-doped marcasite FeTe 2 crystals are a good candidate for thermoelectric applications due to the sharp increase in density of states around the band edges, which favors a large increase in the thermoelectric power factor S 2 σ, where S is the thermopower and σ is the electrical conductivity. 5 …”

Synthesis, Transfer, and Properties of Layered FeTe2 Nanocrystals

“…Layered iron chalcogenides such as selenide (FeSe) − and tellurium-doped FeSe (FeTe x Se 1–x ) , are well-known superconductors, although the parent compound FeTe is nonsuperconducting and has an antiferromagnetic ground state. ,, A minor change in their structure or element composition will strongly affect their electronic and magnetic properties, which are closely correlated. − The study of low-dimensional materials with simple crystal structure and high anisotropy is helpful for understanding the superconductivity and magnetism of these compounds and the interplay between them. Iron dichalcogenides FeX 2 (X = S, Se, Te) are typically crystallized in either nonlayered pyrite or nonlayered marcasite phase structures. − Pyrite phase FeS 2 , marcasite phase FeSe 2 and FeTe 2 are the most stable structures at ambient condition, and all are semiconductors with the band gap decreasing as the chalcogen atom number increases. − Those materials would be potential candidates for solar cells, optoelectronic devices, photocatalysis, and thermoelectronics due to their narrow band gap, large optical absorption coefficient, and large thermoelectric power. ,− Marcasite FeTe 2 ( m -FeTe 2 ) is considered as antiferromagnetic, , and antiferromagnetic to ferromagnetic transition accompanied by semiconductor-metallic transition was observed recently . Different from bulk m -FeTe 2 , monolayer FeTe 2 is calculated to be ferromagnetic. − Hence, synthesis layered FeTe 2 , particularly using a simple method, for example, chemical vapor deposition (CVD), is highly desired, and their properties and applications call for studies.…”

Electrical and Magnetoelectrical Transport in FeTe2 (100) Epitaxial Thin Films

“…With a narrow band gap characterization, Fe chalcogenide materials would be potential candidates in optoelectronic and superconductive transport devices. 13,14 Moreover, a minor change in crystalline structure or element composition strongly affects their electronic and magnetic properties. 15−19 As a representative Fe chalcogenide, the marcasite FeTe 2 (m-FeTe 2 ) with an orthorhombic marcasite structure shows rich magnetic states and novel transport behavior.…”