The ALD‐MLD Growth of a ZnO‐Zincone Heterostructure

Abstract

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.

Inflammatory Bone Resorption and Antiosteosarcoma Potentials of Zinc Ion Sustained Release ZnO Chips: Friend or Foe?

“…Because of the self-limited nature of ALD, atomic scale control of film thickness is possible, which is directly connected to the precise amount of released Zn ions. As reported by Choudhury et al, a single cycle of the ALD process produces ∼200 ng/cm 2 ZnO; the total amount of ZnO on 35 mm-diameter glass slides with 400-cycled ZnO is approximately ∼0.8 mg . ALD was performed in the Lucida D-100 chamber, with DEZ–purge–water–purge cycles controlled at 0.5 s–10 s–0.1 s–30 s. The deposition temperature was fixed at 150 °C.…”

Stability of molecular layer deposited zincone films: experimental and theoretical exploration

“…Molecular layer deposition was carried out in a laminar "ow type" custom built ALD reactor described elsewhere. 32 Self saturating surface chemistry with diethylzinc (DEZ, Sigma Aldrich) and hydroquinone (HQ, Sigma Aldrich) was used for the growth of zincone lms at 150 C. The zincone chemistry can be described by two half-surface chemical reactions as reported earlier, where * denotes the surface species for reactions. DEZ was kept at room temperature while HQ was heated to 130 C with overhead N 2 ow arrangement for better vapour transport to the reactor.…”

“…250 MLD cycles of zincone lm growth. 32 The decrease in resistance during deposition can be attributed to many possible phenomena namely surface or interface scattering, phonon scattering etc. either acting independently or additively.…”

“…23,[26][27][28] Recently, homo/hetero bifunctional aromatic molecules are being used to replace the popularly used linear organic ones. [29][30][31] However, the rigidity of the aromatic compounds though provides structural stability to the materials, does not offer any permanent solution to the persisting chemical instability 32 of the hybrid lms.…”

Comparison on atomic/molecular layer deposition grown aluminum alkoxide polymer films using alkane and alkyne organic precursors

“…21,22 Although homobifunctional in nature, the presence of a stiff benzene backbone prevents the possibility of the molecule to react twice in such cases. 27,28 Aromatic homobifunctional organic precursor based hybrid films overcome the disadvantage of double reactions, however, at the expense of higher deposition temperatures 1,27 The extremely low vapor pressure of most of the aromatic organic precursors necessitating higher annealing temperature of the compounds limits the possibility of depositing hybrid films at lower temperatures. This restricts the applicability of the organic-inorganic films in various fields especially for temperature sensitive applications.…”