Electrical and microwave dielectric properties of K2Nb8O21 microwires

K2Nb8O21 microwires with diameters of several hundred nanometers and lengths up to tens of microns were prepared by molten salt synthesis, and characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The as-synthesized microwires have semiconductor characteristics with band gap Eg of about 3.1 eV, consistent with electrical transport measurement of single microwire, which gives a resistivity of about 0.46 Ω m at room temperature. Microwave dielectric property measurement at 2–18 GHz shows that K2Nb8O21 microwires have a relative low complex permittivity. A weak dielectric relaxation occurs in the 12–16 GHz band due to the free charges polarization on the interfaces between K2Nb8O21 microwires and the PVB matrix.