Strain Effects on the Electronic and Optical Properties of Kesterite Cu2ZnGeX4 (X = S, Se): First-Principles Study

Abstract

Following the chronological stages of calculations imposed by the WIEN2K code, we have performed a series of density functional theory calculations, from which we were able to study the effect of strain on the kesterite structures for two quaternary semiconductor compounds Cu2ZnGeS4 and Cu2ZnGeSe4. Remarkable changes were found in the electronic and optical properties of these two materials during the application of biaxial strain. Indeed, the band gap energy of both materials decreases from the equilibrium state, and the applied strain is more pronounced. The main optical features are also related to the applied strain. Notably, we found that the energies of the peaks present in the dielectric function spectra are slightly shifted towards low energies with strain, leading to significant refraction and extinction index responses. The obtained results can be used to reinforce the candidature of Cu2ZnGeX4(X = S, Se) in the field of photovoltaic devices.

Ab Initio Study of Carrier Mobility, Thermodynamic and Thermoelectric Properties of Kesterite Cu2ZnGeS4

“…As shown in Table 1 , the calculated exciton binding energy and static dielectric constant are 59.03 meV and 5.88 meV, respectively. The latter has been evaluated from the interband-related optical response investigated in a previous work [ 17 ]. There, a value of 2.42 was found for the CZGS static index of refraction.…”

“…The electronic, structural, and optical properties of kesterite materials have been quite extensively investigated using first-principles calculations [ 12 , 13 , 14 , 15 , 16 , 17 ]. Utilizing numerical simulations and modeling is an interesting strategy for studying such properties.…”

“…One of the distinguishing features of our study will be the use of the modified Becke–Johnson potential, combined with the Hubbard potential U (mBJ+U), as an exchange-correlation functional. Since it has been shown that the mBJ+U approach is a suitable tool for describing the electronic properties of CZGS [ 17 ], we shall apply the same formalism as the basis for determining the main thermodynamic, transport, and thermoelectric properties of this compound. In advance, it is possible to assert that, according to our results, kesterite CZGS would be an excellent candidate for thermoelectric applications.…”

Tuning the Electronic Properties of Janus GeSnS2 Monolayers through Strain and Electric Field

“…The biaxial strain applied to the GeSnS2 monolayer is defined as ε = a−a 0 a 0 , where a and a 0 represent the strained and unstrained lattice constants, respectively [16,17]. In addition, we incorporated an external electric field E perpendicular to the 2D surface of the GeSnS2 to investigate its impact on the system.…”

Structural, optoelectronic, and magnetic behaviors of Li2BeTM (TM = V, Cr, Mn, Fe) Se4 compounds using DFT investigations

“…However, a close inspection reveals that the stability problems arise naturally in the examination of such materials. To overcome these issues, other absorbers have been studied which belong to the I 2 -II-IV-VI 4 type involving various atomic configurations [17][18][19]. An inspection shows that such materials involve particular crystallized structures including either the zinc blende, the wurtzite, the stannite or the kesterite phases [20].…”