Bipolar Charge Storage Characteristics in Copper and Cobalt Co-doped Zinc Oxide (ZnO) Thin Film

作者：Kumar Amit; Herng Tun Seng; Zeng Kaiyang^*; Ding Jun

来源：ACS Applied Materials & Interfaces, 2012, 4(10): 5276-5280.

DOI：10.1021/am301220h

• zinc oxide
• codoped ZnO
• Kelvin probe force microscopy
• bipolar charge
• charge stability

The bipolar charge phenomenon in Cu and Co co-doped zinc oxide (ZnO) film samples has been studied using scanning probe microscopy (SPM) techniques. Those ZnO samples are made using a pulsed laser deposition (PLD) technique. It is found that the addition of Cu and Co dopants suppresses the electron density in ZnO and causes a significant change in the work Fermi level) value of the ZnO film; this results in the ohmic nature of the contact between the electrode (probe tip) and codoped sample, whereas this contact exhibits a Schottky nature in the undoped and single-element-doped samples. These results are verified by Kelvin probe force microscopy (KPFM) and ultraviolet photoelectron spectroscopy (UPS) measurements. It is also found that the co-doping (Cu and Co) can stabilize the bipolar charge, whereas Cu doing only stabilizes the positive charge in ZnO thin films.

• 出版日期2012-10