Open Access Nano Express

Optical and microstructural properties of ZnO/TiO2 nanolaminates prepared by atomic layer deposition

Yu-Zhu Gu, Hong-Liang Lu*, Yang Geng, Zhi-Yuan Ye, Yuan Zhang, Qing-Qing Sun, Shi-Jin Ding and David Wei Zhang

Author affiliations

State Key Laboratory of ASIC and System, Department of Microelectronics, Fudan University, Shanghai 200433, China

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Citation and License

Nanoscale Research Letters 2013, 8:107  doi:10.1186/1556-276X-8-107

Published: 27 February 2013

Abstract

ZnO/TiO2 nanolaminates were grown on Si (100) and quartz substrates by atomic layer deposition at 200°C using diethylzinc, titanium isopropoxide, and deionized water as precursors. All prepared multilayers are nominally 50 nm thick with a varying number of alternating TiO2 and ZnO layers. Sample thickness and ellipsometric spectra were measured using a spectroscopic ellipsometer, and the parameters determined by computer simulation matched with the experimental results well. The effect of nanolaminate structure on the optical transmittance is investigated using an ultraviolet–visible-near-infrared spectrometer. The data from X-ray diffraction spectra suggest that layer growth appears to be substrate sensitive and film thickness also has an influence on the crystallization of films. High-resolution transmission electron microscopy images show clear lattice spacing of ZnO in nanolaminates, indicating that ZnO layers are polycrystalline with preferred (002) orientation while TiO2 layers are amorphous.

Keywords:
ZnO/TiO2 nanolaminates; ALD; Transmittance; HRTEM