Electronic structural critique of interesting thermal and optical properties of C₁₇Ge germagraphene

Abstract

DATE:In this communication, we report a theoretical attempt to understand the involvement of electronic structure in determination of optical and thermal properties of C 17 Ge germagraphene, a buckled two dimensional material. The structure is found to be a direct bandgap semiconductor with low carrier effective mass. Our study has revealed the effect of spin-orbit coupling on the band structure and in appearance of spin Hall current in the material. A selectively high blue to ultraviolet light absorption and a refractive index comparable to flint glass open up the possible applicability of this material for optical devices. From electronic structural point of view, we investigate the reason behind its moderately high Seebeck coefficient and power factor comparable to traditional thermoelectric materials. Besides its narrow bandgap, relatively smaller work function of C 17 Ge (4.361 eV ) than graphene (4.390 eV ) and germanene (4.682 eV ) assures more easily removal of electron from the surface. This material is turned out to be an excellent alternative for futuristic semiconductor application from optical to thermal device regime.

Semiconductor Physics: A Density Functional Journey

“…If we take inner product of HF Eq. [16] with 𝜓 𝑖 (x) and sum over {𝑖} then the HF total energy 𝐸 [Ψ 𝐻 𝐹 ] in terms of orbital energy 𝜖 𝑖 is found using Eq. [8] as:…”

“…From the last term of Eq. [16] the orbital dependent exchange operator v𝑥,𝑖 (r) and orbital dependent Fermi hole 𝜌 𝑥,𝑖 (r, r ) are defined as [3,4]:…”

“…[19] by 𝜌 𝑥 (r, r ) then, the exchange potential operator v𝑥,𝑖 (r) becomes multiplicative or local operator 𝑣 𝑆 𝑥 (r) and the Hartree-Fock-Slater equation from Eq. [16] using Eq. [9] becomes:…”

“…Similar trend is observed for 2D-graphene (HSE06→ 4.39𝑒𝑉; expt. → 4.56) [16]. Semiconductor band alignment analysis is done for a group of traditional semiconductors in [105] and HSE06 has performed great in locating so.…”

“…Thus, the new era of green energy materials becomes highly dependent on the band-alignment calculation. From three and two dimensional traditional semiconductors like silicon and graphene to relatively new materials C 3 N 4 , silicene, germanene, whenever the exact prediction of work-function is needed, HSE hybrid function is a natural choice for such studies and proved to match the experimental values almost exactly [13][14][15][16].…”