物理化学学报 >> 2004, Vol. 20 >> Issue (06): 631-636.doi: 10.3866/PKU.WHXB20040616

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电容测量研究铬表面氧化膜的半导体性能

孔德生;李亮   

  1. 曲阜师范大学化学系,曲阜　273165; 山东大学化学系,济南　250100
  • 收稿日期:2003-12-11 修回日期:2004-03-05 发布日期:2004-06-15
  • 通讯作者: 孔德生 E-mail:kongds@mail.sdu.edu.cn

The Semiconducting Properties of Oxide Films Formed on Chromium Studied by Capacitance Measurement

Kong De-Sheng;Li Liang   

  1. Department of Chemistry, Qufu Normal University, Qufu　273165;Department of Chemistry, Shandong University, Jinan　250100
  • Received:2003-12-11 Revised:2004-03-05 Published:2004-06-15
  • Contact: Kong De-Sheng E-mail:kongds@mail.sdu.edu.cn

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摘要： 利用电容测量技术,基于Mott-Sckottky分析,研究了在0.5 mol•L－1 H2SO4溶液中铬表面氧化膜的半导体性质,以及膜形成条件的影响.结果表明,铬在钝化电位区内所形成的表面氧化膜具有p-型半导体特性,膜的厚度约(1.2±0.3) nm.膜的阻抗响应表现出低频弥散行为,可以用介电弛豫普适定律来描述.膜的掺杂浓度NA随成膜电位及极化时间的延长而增大,溶液pH值则通过改变膜的表面电荷而影响膜的平带电位EFB.

关键词: 铬, 钝化膜, 电容测量, 受主浓度, 平带电位

Abstract: The semiconducting properties of the oxide film formed on chromium were studied by capacitance measurement and the Mott-Schottky analysis. It is shown that the oxide films formed on chromium within the passive potential region in 0.5 mol•L－1 H2SO4 solution, the thickness of which is about 1.2±0.3 nm, behavior like a p-type semiconductor. The impedance response of the film showed a low-frequency dispersion, which can be accounted for by dielectric relaxation with complex capacitance. The effects of the film-formation potential, the polarization time, and the solution pH on the semiconductive parameters of acceptor density (NA) and flatband potential (EFB) were investigated. The increase of NA corresponds to the increase of the hydration degree of the oxide films. The linear relationship with a slope of ～59 mV/pH unit between EFB and solution pH was observed.

Key words: Chromium, Passive film, Capacitance measurement, Acceptor density, 　Flatband potential