Synthesis of Single-crystalline KNbO3 Nanowires with a Sacrificial Template Method and Their Second Harmonic Generation Response

High yield orthorhombic single-crystalline KNbO3 nanowires with widths of 60∼150 nm and lengths up to a few microns were synthesized, using Nb2O5 nanobelts as reactants as well as templates via the hydrothermal process. The products were determined by XRD, and the morphology and the structure were characterized by SEM, TEM, HRTEM, and SAED techniques. The growth direction of KNbO3 was determined to be the [001] crystallographic direction. Results show that synthesized nanowires exhibit a second harmonic generation (SHG) response, an efficient nanoscale second harmonic light source. The excellent nonlinear optical properties of KNbO3 have potential applications in nano-optical devices.