采用电化学方法以及Mott-schottky理论,研究了两种不同晶粒大小的铜在不同Cl-浓度溶液中的钝化膜形成过程和机理,计算了不同Cl-浓度溶液中铜在0.2V、0.4V两种电位下阳极氧化后钝化膜中的载流子密度。结果表明:铜在不同条件下表面氧化膜的Mott-schottky曲线线性斜率为负,呈现P型半导体的性质,膜中的多数载流子为空穴。随着铜晶粒度的增大和阳极钝化电位的升高,铜表面钝化膜中的受主密度NA降低;随着介质溶液中的Cl-浓度的升高,钝化膜中的受主密度NA不断增大。
The formation process and mechanism of passive film on Cu with two different grain sizes in solutions with different Cl-concentrations were studied by electrochemical methods and Mott-Schottky theory.The carrier density in the passive film formed at two oxidation potentials(0.2 V,0.4 V) in the solutions with different Cl-concentrations was calculated.The results indicated that under different conditions,the Mott-Schottky plots of the oxide films on the surface of Cu were linear with a negative slop and showed the behavior of P-type semiconductor.The majority carriers in the passive film were holes.With the increase of the grain size of Cu and the increase of anodic passivation potential,the acceptor density(NA) in the passive film formed on the surface of Cu reduced.When the concentration of Cl-in the medium solution increased,the acceptor density(NA) in the passive film increased.