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Developing high-transmittance heterojunction diodes based on NiO/TZO bilayer thin films

Chia-Cheng Huang1, Fang-Hsing Wang1, Chia-Ching Wu2, Hong-Hsin Huang3 and Cheng-Fu Yang4*

Author affiliations

1 Department of Electrical Engineering, National Chung Hsing University, Taichung, 402, Taiwan

2 Department of Electronic Engineering, Kao Yuan University, Kaohsiung, 821, Taiwan

3 Department of Electrical Engineering, Cheng-Shiu University, Kaohsiung, 833, Taiwan

4 Department of Chemical and Materials Engineering, National University of Kaohsiung, Kaohsiung, 811, Taiwan

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Citation and License

Nanoscale Research Letters 2013, 8:206  doi:10.1186/1556-276X-8-206

Published: 1 May 2013


In this study, radio frequency magnetron sputtering was used to deposit nickel oxide thin films (NiO, deposition power of 100 W) and titanium-doped zinc oxide thin films (TZO, varying deposition powers) on glass substrates to form p(NiO)-n(TZO) heterojunction diodes with high transmittance. The structural, optical, and electrical properties of the TZO and NiO thin films and NiO/TZO heterojunction devices were investigated with scanning electron microscopy, X-ray diffraction (XRD) patterns, UV-visible spectroscopy, Hall effect analysis, and current-voltage (I-V) analysis. XRD analysis showed that only the (111) diffraction peak of NiO and the (002) and (004) diffraction peaks of TZO were observable in the NiO/TZO heterojunction devices, indicating that the TZO thin films showed a good c-axis orientation perpendicular to the glass substrates. When the sputtering deposition power for the TZO thin films was 100, 125, and 150 W, the I-V characteristics confirmed that a p-n junction characteristic was successfully formed in the NiO/TZO heterojunction devices. We show that the NiO/TZO heterojunction diode was dominated by the space-charge limited current theory.

Titanium-doped zinc oxide; Nickel oxide; Heterojunction diode; Space-charge limited current