Electronic behavior of native oxide films on Ti and TiN during 90-day immersion in electrolytes with different pH levels
来源期刊：Rare Metals2021年第3期
论文作者：Amir Poursaee Golnaz Najaf-Tomaraei Marian S.Kennedy
摘 要：This work presents the electronic behavior of Ti and TiN thin films when exposed to electrolytes with pH levels of 2,7 and 13 for 90 days.Staircase potentio-electrochemical impedance spectroscopy tests were performed on the 100-nm Ti and TiN monolithic films,and MottSchottky analysis of these tests was used to determine the films’ semiconductive behavior and changes in the donor/acceptor density.In addition,the flat-band potential of each film’s surface oxide was also characterized.No attempt was made to control oxide formation,and therefore,these tests reflected the native surfaces of these films.While the TiN films exhibited n-type semiconductivity in all electrolytes,the Ti films only showed n-type behavior in the acidic（pH=2） and neutral（pH=7） electrolytes.The semiconductivity of the Ti films transitioned to p-type during exposure to the basic electrolyte（pH=13） after reaching 60 days.Furthermore,there was a significant increase in the donor densities for both Ti and TiN films when immersed in the basic electrolyte relative to the acidic and neutral electrolytes.
Amir Poursaee1，Golnaz Najaf-Tomaraei2，Marian S.Kennedy2
1. Department of Materials Science and Engineering and Glenn Department of Civil Engineering,Clemson University2. Department of Materials Science and Engineering,Clemson University
摘 要：This work presents the electronic behavior of Ti and TiN thin films when exposed to electrolytes with pH levels of 2,7 and 13 for 90 days.Staircase potentio-electrochemical impedance spectroscopy tests were performed on the 100-nm Ti and TiN monolithic films,and MottSchottky analysis of these tests was used to determine the films’ semiconductive behavior and changes in the donor/acceptor density.In addition,the flat-band potential of each film’s surface oxide was also characterized.No attempt was made to control oxide formation,and therefore,these tests reflected the native surfaces of these films.While the TiN films exhibited n-type semiconductivity in all electrolytes,the Ti films only showed n-type behavior in the acidic（pH=2） and neutral（pH=7） electrolytes.The semiconductivity of the Ti films transitioned to p-type during exposure to the basic electrolyte（pH=13） after reaching 60 days.Furthermore,there was a significant increase in the donor densities for both Ti and TiN films when immersed in the basic electrolyte relative to the acidic and neutral electrolytes.
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