阳极氧化铅膜的光电流频谱曲线随膜增厚而位移的研究

Study on the Shift of the Photocurrent Spectral Curves for Anodic Plumbous Oxide Film with Increasing the Thickness of the Film

铅在硫酸溶液中生长的阳极氧化铅膜的光电流频谱曲线随着膜增厚而红移。Dimitrov等认为长波对光电流的贡献随着膜的增厚而增大的程度要较短波的为大,从而导致曲线的位移。我们的研究表明其主要原因为膜中的t-PbO和o-PbO的比例随膜增厚而发生的变化,并非如上所述。本工作求出上述阳极膜中的t-PbO和o-PbO的禁带宽度分别为1.9和2.6eV。

The shift of the photocurrent spectral ourves toward longer wavelengths for anodic plumbous oxide film in sulfuric acid solution with increasing the thickness of the film was explained by Dimitrov et al. that this is due to the less absorption of light at longer wavelengths, and as the thickness of the film increases, the contribution of the longer wavelengths is enhanoed, leading to the observed shifting of the spectral curves. According to our study, the major reason for the shift of the curves is the change of the ratio of the amounts of t-PbO and o-PbO in the said film with increasing the thickness of the film, but not the above mentioned one. The bandgap energies of t-PbO and o-PbO in the mentioned film, which were determined in the present work. are 1.9 and 2.6 eV, respectively.