ZnO ALD films were grown directly on graphene powders using a rotary ALD reactor. For the ZnO ALD, diethyl Zinc(ZnCH2CH3)2) and high performance liquid chromatography (HPLC) grade H2O were obtained from Sigma-Aldrich. The typical growth rate for the ZnO ALD chemistry is 2 per cycle. ZnO ALD is performed using alternating Zn(CH2CH3)2 and H2O exposures: