Oxygen vacancies and hydrogen in amorphous In-Ga-Zn-O and ZnO
Physical Review Materials
American Physical Society (APS)
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Li, H., Guo, Y., & Robertson, J. (2018). Oxygen vacancies and hydrogen in amorphous In-Ga-Zn-O and ZnO. Physical Review Materials, 2 (7) https://doi.org/10.1103/PhysRevMaterials.2.074601
Hydrogen is known to be present as an impurity in amorphous oxide semiconductors at the 0.1% level. The behavior of hydrogen and oxygen vacancies in amorphous In-Ga-Zn-O is studied using density functional supercell calculations. We show that the hydrogens pair up at oxygen vacancies in the amorphous network, where they form metal-H-metal bridge bonds. These bonds are shown to create filled defect gap states lying just above the valence band edge, infrared modes at about 1400 and 1520cm−1, and they are shown to give a consistent mechanism to explain the negative bias illumination stress instability found in oxide semiconductors such as In-Ga-Zn-O (IGZO).
The authors acknowledge funding from EPSRC Grants No. EP/P005152/1.
Engineering and Physical Sciences Research Council (EP/P005152/1)
External DOI: https://doi.org/10.1103/PhysRevMaterials.2.074601
This record's URL: https://www.repository.cam.ac.uk/handle/1810/284961