Tuning optical properties of transparent conducting barium stannate by dimensional reduction

Abstract

We report calculations of the electronic structure and optical properties of doped n-type perovskite BaSnO3 and layered perovskites. While doped BaSnO3 retains its transparency for energies below the valence to conduction band onset, the doped layered compounds exhibit below band edge optical conductivity due to transitions from the lowest conduction band. This gives absorption in the visible for Ba2SnO4. Thus it is important to minimize this phase in transparent conducting oxide (TCO) films. Ba3Sn2O7 and Ba4Sn3O10 have strong transitions only in the red and infrared, respectively. Thus there may be opportunities for using these as wavelength filtering TCO.

Transparent conducting properties of SrSnO3 and ZnSnO3

“…2. The calculated band gap of BaSnO 3 by the same method is 2.82 eV and is indirect, with an onset of optical absorption from direct transitions at ∼3.2 eV, 17,24 in excellent accord with experimental data. 12 Band structures of ZnSnO 3 using standard GGA functionals have been reported by Wang and co-workers 51 and by Zhang and co-workers.…”

“…These include additional absorption in heavily doped materials both from the Drude tail [14][15][16] and from interband transitions involving the doped carriers. 17 The former gives absorption primarily in the infrared and red, while the latter can be at any wavelength and depends on the details of the band structure. Within the Drude model, σ(ω) = σ 0 /(1 + iωτ), where τ is an inverse scattering rate and σ 0 is the DC conductivity, σ 0 = ω 2 p τ.…”

“…18 As mentioned, BaSnO 3 shows considerable promise as a new n-type transparent conducting oxide (TCO). This material, which has a simple s-band electronic structure, 17,[19][20][21][22][23][24] is dopable to a highly conductive state using Sb or La, 25 and has been developed as a high performance TCO. [6][7][8][9][10][11][12] The related compounds, CaSnO 3 and SrSnO 3 , occur in distorted orthorhombic perovskite structures, 26 while ZnSnO 3 occurs in a ferroelectric LiNbO 3 type structure.…”

Sn(II)-Containing Phosphates as Optoelectronic Materials

“…To address this important, but often neglected aspect, we calculate absorption spectra with virtual crystal doping. This allows transitions from lower bands into the now empty states at the top of the valence band [39,40]. The calculated absorption spectra with p-type virtual crystal doping of 0.05 holes per Sn are shown in the inset of Fig.…”

“…These were done based on first principles DFT calculations combined with the particle swarm optimization algorithm as implemented in the CALYPSO code [36,37]. We also particularly calculated the optical absorption spectra of the compounds when doped [38][39][40]. This is an important but often neglected aspect for identifying transparent conductors.…”