Anomalously Large Pockels Effect in ZnO-F Single Crystalline Films Deposited on Bare Glass

Large linear electrooptics (the Pockels effect) of up to 17 pm/V for the wavelength 435 nm has been observed in ZnO films doped by fluorine and deposited on bare glass. In order to describe the phenomenon observed, a complex approach, including self-consistent band structure calculations together with the appropriate molecular dynamics simulations of the interfaces, was applied. The origin of the effect observed is linked to substantial charge density non-centrosymmetry between the wurtzitelike crystalline films and the bare glass substrate, as well as to additional charge density polarisation caused by the fluorine.