Spontaneous polarization induced growth of ZnO nanostructures

We report the success of controlled synthesis of freestanding ZnO nanobelts whose surfaces are dominated by the large polar surfaces. The nanobelts grow along the - axis, their large top/bottom surfaces are the ±(0001) polar planes, and the side surfaces are (01 | 0). Owing to the positive and negative ionic charges on the zinc- and oxygen-terminated ±(0001) surfaces, respectively, the nanobelts form multi-loops of nanohelixes/nanosprings for the sake of reducing electrostatic energy introduced by the polar surfaces. The polar surface dominated ZnO nanobelts/nanohelixes are likely to be useful building blocks for nanodevices in MHMS/NEMS or biosensors.