Homogeneity of composition in evaporated Pb_(1-x)Ge_xTe thin films

摘要

PbTe based semiconductors are well-known narrow gap Ⅳ-Ⅵ compounds, which are of interest due to potential application in the fabrication of photo-detectors in the mid- and far infrared spectral range. Among them, Pb_(1-x)Ge_xTe is known to have wider band gap than PbTe, which has been used to fabricate photo-detectors with shorter wavelength (λ < 6.7 μm). However, the homogeneity of composition in evaporated Pb_(1-x)Ge_xTe thin films directly from bulk alloys has not been investigated. In the paper, we report the investigation that the homogeneity of composition on the surface was studied using energy-dispersive X-ray analysis (EDAX), and the compositional depth profiles was investigated using Auger electron spectroscopy (AES) in combination with argon ion sputtering. ASE depth profiling and characterization of details in the Ge concentration gradient is demonstrated.