We investigated the mole-controlled growth of Y-doped ZnO (YZO) nanostructures by the hydrothermal synthesis techniques. Through controlling the aqueous solution's mole concentration, we could modify the morphological and structural properties of YZO. The shape of YZO becomes a nanometer-sized rod when using a relatively low mole concentration, whereas the morphology is changed to be flat and mosaic when using a relatively high mole concentration. Since the aqueous solution's mole concentration decides the amount of hydroxide, we ascribe the mole-controlled morphological changes to the alteration of chemical potential during the hydrothermal chemical reaction. (C) 2014 Elsevier B.V. All rights reserved.