Structural, optical, dielectric relaxation, complex impedance and modulus spectroscopic studies of pure and glutamic acid doped potassium dihydrogen phosphate

Abstract

The slow evaporation procedure is used to develop KDP crystals with both pure and doped by glutamic acid. The powder XRD patterns reveal single phase, lower lattice strain and enhancement of peak intensity due to doping in KDP. Doping is observed to increase the crystals' nonlinear property, second harmonic generating efficiency. The UV–VIS spectra indicate slight decrement in the transmittance due to doping. The energy band gap is evaluated from Tauc’s plot and KM theory and slight reduction is observed on doping. The refractive index of pure and doped KDP crystals within visible region is observed to vary between 1.52 to 1.64. The dielectric constant and loss have shown normal behavior with respect to applied frequency of electric field at room temperature. The complex impedance and modulus plots show single semicircle for pure and doped KDP due to grain contribution only and exhibits non-Debye type relaxation. The Jonscher’s power law is applied to ac conductivity data and ideal long-range pathways and diffusion limited hopping mechanism is confirmed.