First-principle study of electronic structure and optical properties of SiC nano films

Abstract

The structure, electronic and optical properties of 3C-SiC nano films were calculated according to first principles based on density functional theory. It is manifested that the nano films were structurally stable when the number of layers was increased to 12. Compared with bulk counterparts, nano films displayed narrower band gaps, and their Fermi energy levels were brought into the conduction band. The ε 2 (ω) of dielectric function, extinction coefficient, and absorption coefficient of the nano films were greater than that of the bulk in the ultraviolet range. With the layer numbers decreased, the values increased in the range. The results provide a guideline for 3C-SiC nano films to work for UV detectors.

The impact of Ni and Zn doping on the thermal durability and thermoelectric variables of pristine CuSe nanoparticles

“…42,43 The XPS profiles of Se 2d for all samples exhibit two photoelectron bands with binding energy values of 54.2 eV and 55.0 eV, designated as Se 2d 5/2 and Se 2d 3/2 , respectively, known as standard peaks of Se. 2–42,44 The identical patterns of both of the Cu 2p peaks and Se 3d peaks for each nanoparticle indicate the existence of CuSe.…”

“…Analyzing the prospective utility of the as-synthesized nanoparticles as thermoelectric materials necessitates an examination of their thermal stability, which is important to underpin consistent and efficient performance for the device. The thermogravimetric and differential thermogravimetric profiles for pure CuSe nanoparticles have been described by Josephine Ying Chyi Liew et al 27 and Ibrahim Garba Shitu et al 28 Also, Huan Luo et al conducted a thorough thermal study with kinetic parameters for a pure CuSe compound. 29 But as far as the present researchers are cognizant, neither any thorough thermal study of 5% and 10% Ni-doped CuSe nanoparticles nor that of 5% and 10% Zn-doped CuSe nanoparticles has previously been described.…”

Electron-Coupled Proton Transfer Governed Magnetic Spin Couplings and Switching in Defect Nano Silicon Carbide

“…Besides, Ginsberg also proposed a calculation method of the energy difference between the pure singlet and triplet states, that is, Δ E ST = ⟨ S 2 ⟩ T J . We also use the exchange–correlation functional PW91 (its keyword is PW91PW91 in the INPUT line) to verify the accuracy of J because PW91 has been widely used to study the properties of the SiC nanomaterials, such as the structural characteristics, electronic properties, weak interaction, and magnetism. − …”

Magnetic couplings and applied electric field regulation in diradical SiC defect diamond-like nanoclusters

“…52 The functional PW91 has been widely used to study the properties of SiC nanomaterials, such as SiC nanostructures, the electronic structures and optical properties of SiC nano films, the hydrogen storage properties of the weak interaction between SiC nanotubes and H 2 molecules, and the ordered vacancy magnetism of two-dimensional SiC, which obtain better theoretical results. [53][54][55][56][57][58] Among other things, the BS state is determined by the Noodleman method, and the J value is calculated with the formula J = (E BS À E T )/(hS 2 i T À hS 2 i BS ), where E BS and E T are the corresponding total energies of the defect clusters in the BS and T states, while hS 2 i BS and hS 2 i T are the corresponding average spin squared values. 59,60 In addition, the external factor, especially the applied electric field, is worth considering, because it can very effectively promote the redistribution of electron density in the defect center, to regulate and change the magnetic coupling.…”