Multiple NaNbO3 nanoplates are created within Nb2O5 nanotubes forming a unique class of heterostructure nanotubes combining ferroelectric and semiconducting nanomaterials. Local piezoelectric studies on NaNbO3 nanoplates show clear ferroelectric behavior (see figure), while the semiconductive properties of the host Nb2O5 nanotubes allows for switching of the electrical conductivity by an external electric field.