Negative capacitance in ZnO1-xChx (Ch=S, Se, Te): Role of localized charge recombination.

We demonstrate negative capacitance (NC) dispersion in ZnO by doping lesser electronegative chalcogen (Ch=S, Se, Te) elements at the oxygen (O)-site. Approximately 4.00×0.15 atomic percentage of ChOX is obtained from Rietveld refinement. Using ab initio and dielectric spectroscopy, the tailoring of charge localization around dopants and consequent charge recombination are observed to have a systematic dependence on the stabilization of NC. With the increase of dopant electronegativity difference from SOX to TeOX, the low frequency (<100Hz) dispersion of NC gradually extends to a larger frequency under lower external bias. Universal Debye response is found to govern the NC dispersion with calculated relaxation time indicating to trap mediated charge recombination. [ABSTRACT FROM AUTHOR]