The ALD-MLD Growth of a ZnO-Zincone Heterostructure


  • The authors thank the Board of Research in Nuclear Sciences (DAE-BRNS) for financial support. The authors would also like to thank UGC-DAE Consortium for Scientific Research, Indore for X-Ray reflectivity measurement and Sophisticated Analytical Instrument Facility (SAIF), IIT Bombay for analytical measurements.


A mixed inorganic/organic zinc oxide/zincone multilayer film, using a combination of atomic layer deposition (ALD) and molecular layer deposition (MLD), is grown. A molecular fragment is deposited in each half reaction in the MLD technique, thus making it similar to, and compatible with, the ALD method of deposition. Zinc oxide inorganic layers are grown at a substrate temperature of 150°C with alternate surface-saturating reactions of diethylzinc and water. Under similar growth condition, diethylzinc and hydroquinone are used to deposit an organic zincone layer that follows the MLD reaction mechanism. Deposition rates are obtained from an in-situ quartz crystal microbalance (QCM) and verified using X-ray reflectivity (XRR) measurements and scanning electron microscopy (SEM). Chemical constituents of the hybrid layers are confirmed from secondary ion mass spectroscopy (SIMS) and Fourier transform infrared (FTIR) spectroscopy. Selective etching of the organic layers results in the formation of zinc oxide nanosheets stacked together by van der Waals attraction balanced by Coulombic repulsion.