One-photon band gap engineering of borate glass doped with ZnO for photonics applications

Lithium tungsten borate glass of the composition (0.56- x )B 2 O 3 -0.4Li 2 O- x ZnO-0.04WO 3 (0 ≤ x ≤ 0.1 mol. %) is prepared for photonics applications. The glass is doped with ZnO to tune the glass absorption characteristics in a wide spectrum range (200-2500 nm). Chemical bond approach, including chemical structure, electronegativity, bond ionicity, nearest-neighbor coordination, and other chemical bonding aspect, is used to analyze and to explain the obtained glass properties such as: transmittance, absorption, electronic structure parameters (bandgap, Fermi level, and Urbach exciton-phonon coupling), Wannier free excitons excitation (applying Elliott's model), and two-photon absorption coefficient as a result of replacement of B 2 O 3 by ZnO.