In this paper, we show the usefulness of photoacoustic spectroscopy (PAS) to monitor the intermixing at the thin films heterojunction. CdTe/CdS bilayers with different thicknesses were used to analyze the effect of S-Te interdiffusion on the PAS spectra. Unlike the spectrum measured by the optical transmittance technique, the photoacoustic spectrum shows an optical absorption band, in addition to the absorption edge corresponding to the CdTe layer. The position of the band changes from 2.31 to 1.93 eV depending on the CdTe layer thickness in the structure. The band shifts were associated with the composition of the ternary CdS_1-xTe_x alloy at the interface. Our interpretation of the results was supported by the PAS-Phase-Resolved and the X-Ray photoelectron spectroscopy techniques.

在本文中，我们展示了光声光谱 (PAS) 在监测薄膜异质结处的混合方面的有用性。使用不同厚度的 CdTe/CdS 双层来分析 S-Te 相互扩散对 PAS 光谱的影响。与通过光透射技术测量的光谱不同，光声光谱除了对应于 CdTe 层的吸收边外，还显示出一个光吸收带。根据结构中的 CdTe 层厚度，能带的位置从 2.31 到 1.93 eV。能带位移与界面处的三元 CdS _1-x Te _x合金的成分有关。我们对结果的解释得到了 PAS-Phase-Resolved 和 X 射线光电子能谱技术的支持。