Influence of Cu 2 S, SnS and Cu 2 ZnSnSe 4 on optical properties of Cu 2 ZnSnS 4

Abstract

We have studied influence of Cu 2 ZnSnSe 4 (CZTSe) and secondary phases of Cu 2 S and SnS on optical properties of kesterite-type Cu 2 ZnSnS 4 (CZTS) by using the effective medium theory. We found that CZTSe and Cu 2 S cause band gap reduction and enhance light absorption of CZTS at all photon energies of the sunlight whereas SnS changes optical properties of CZTS only at large photon energies beyond the solar spectrum. Optical spectra of CZTS(Se) has been studied by first principles calculations within hybrid functional that was used as input for the effective medium theory.

Kesterite Cu 2 ZnSnS 4 thin films synthesized utilizing electrodeposition: Influence of metal doping on the properties

“…The large energy gap value of the doped Sb, Cr, and Li samples could have been due to low crystallinity, the presence of secondary phases, and the formation of impurities such as Cu 2 SnS 3 and CTS that affected the grain size and/or mixed surface morphology 35 . The formation of Cu 2 S phases increased the band gap of the CZTS 26 . Since Cu 2‐x S secondary phases occurred in both the CZTS‐Li and CZTS‐Cr samples, the high band gap could have been due to the effect of secondary phases.…”

“…Main secondary phases related to compounds such as CuS 2 , ZnS, and SnS 2 were also not detected. 26 Figure 4 displays the FE-SEM results of the CZTS thin-film layers coated with Li, Cr, Sb, and Na via sulfurization at 580 C. Figure 4A displays the surface morphology of the sample CZTS-Li has a rugged morphology composed of small grains of 300 to 500 nm in size. The film was compact and uniform with a dense microstructure containing voids.…”

Magnetism of Kesterite Cu2ZnSnS4 Semiconductor Nanopowders Prepared by Mechanochemically Assisted Synthesis Method

“…The latter aspect stems mainly from the compound's capability to exist in stable forms with significant non-stoichiometry (e.g., copper rich or copper poor), with variable/interchangeable atom sites in the crystal lattice (e.g., Cu/Zn ordered or disordered polymorphs, kesterite vs. stannite structures), and relatively easily accommodating various structural defects (e.g., vacancies, nanophase segregation) to name the most outstanding [6][7][8][9][10][11][12]. It is also worth pointing out that the chemistry leading to the quaternary kesterite is by the very nature complex and often leads to detectable amounts of post-synthesis impurities or by-products including the relevant binary and ternary metal sulfides [13][14][15][16]. All this seems to effect investigations of kesterite by way of making them inadvertently more of the case than clear-cut fundamental studies of the still poorly reproducible syntheses.…”

Optical Properties of Cu2ZnSn(SxSe1‐x)4 by First‐Principles Calculations

“…Recently, Li et al calculated the dielectric function of the kesterite phase using the modified meta‐GGA of Becke–Johnson (mBJ) functional for an eight atom supercells and a 20 × 20 × 20 k ‐mesh. There has also been a number of hybrid functional calculations, in the Heyd–Scuseria–Ernzerhof variant of 2006 (HSE06) . For a number of inorganic compounds, hybrid functionals have been shown to exhibit higher accuracy than computationally inexpensive calculations based on semi‐local exchange‐correlation functional.…”