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Structural, electrical, and optical properties of Ti-doped ZnO films fabricated by atomic layer deposition

Zhi-Yuan Ye, Hong-Liang Lu*, Yang Geng, Yu-Zhu Gu, Zhang-Yi Xie, 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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Nanoscale Research Letters 2013, 8:108  doi:10.1186/1556-276X-8-108

Published: 27 February 2013


High-quality Ti-doped ZnO films were grown on Si, thermally grown SiO2, and quartz substrates by atomic layer deposition (ALD) at 200°C with various Ti doping concentrations. Titanium isopropoxide, diethyl zinc, and deionized water were sources for Ti, Zn, and O, respectively. The Ti doping was then achieved by growing ZnO and TiO2 alternately. A hampered growth mode of ZnO on TiO2 layer was confirmed by comparing the thicknesses measured by spectroscopic ellipsometry with the expected. It was also found that the locations of the (100) diffraction peaks shift towards lower diffraction angles as Ti concentration increased. For all samples, optical transmittance over 80% was obtained in the visible region. The sample with ALD cycle ratio of ZnO/TiO2 being 20 had the lowest resistivity of 8.874 × 10−4 Ω cm. In addition, carrier concentration of the prepared films underwent an evident increase and then decreased with the increase of Ti doping concentration.

TZO films; ALD growth rates; Structure characteristics; Optical properties; Electrical properties