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 Mott–Schottky 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.

中文翻译：

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在不同 pH 值的电解质中浸泡 90 天期间，Ti 和 TiN 上的天然氧化膜的电子行为

这项工作展示了 Ti 和 TiN 薄膜在暴露于 pH 值为 2、7 和 13 的电解质 90 天时的电子行为。对 100 nm Ti 和 TiN 单片薄膜进行了阶梯电位电化学阻抗谱测试，并使用这些测试的莫特-肖特基分析来确定薄膜的半导体行为和供体/受体密度的变化。此外，还表征了每个薄膜表面氧化物的平带电位。没有尝试控制氧化物的形成，因此，这些测试反映了这些薄膜的自然表面。虽然 TiN 薄膜在所有电解质中都表现出 n 型半导体，但 Ti 薄膜仅在酸性 (pH = 2) 和中性 (pH = 7) 电解质中表现出 n 型行为。在暴露于碱性电解质 (pH = 13) 60 天后，Ti 薄膜的半导体转变为 p 型。此外，相对于酸性和中性电解质，当浸入碱性电解质时，Ti 和 TiN 膜的供体密度显着增加。