Dielectric and structural characteristics of the Bi-As₂S₃ quasibinar chalcogenides

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• 作者：M.V. &Scaron ; iljegović^a ; ^{mirjana.siljegovic@df.uns.ac.rs} ; S.R. Lukić Petrović^a ; D.M. Petrović^a ; D.L. Sekulić^b ; G.R. &Scaron ; trbac^a ; F. Skuban^a
• 关键词：Permittivity ; Raman spectra ; DSC measurements ; Chalcogenides
• 刊名：Journal of Non-Crystalline Solids
• 出版年：2017
• 出版时间：1 February 2017
• 年：2017
• 卷：457
• 期：Complete
• 页码：152-156
• 全文大小：638 K
• 卷排序：457

文摘

The results of measurements of the real and imaginary part of dielectric permittivity ε of Bi5(As2S3)95 and Bi7(As2S3)93 chalcogenides indicated their usual dispersion behavior. On the other hand, significantly higher values of these two parameters were obtained in the entire frequency measuring range (100 Hz–10 MHz), compared to those that generally characterize chalcogenide glasses. Very high values of dielectric function parameters of the Bi7(As2S3)93 sample was explained by charge carrier accumulation due to reduced mobility at the interface between the phases with different conductivity. The results of Raman spectroscopy have shown the complexity of the sample structure. Namely, significant number of narrow peaks observed in the Raman spectrum proved the existence of several molecular species or clusters i.e. the occurrence of the phase separation. Crystallization of the sample with lower bismuth content observed in differential scanning calorimeter (DSC) curve as a two-stage process is the reason why the significant increase of the real part of ε at higher temperatures could be attributed to the existence of two types of molecular dipoles, that is to molecular phase separation. Their identification was made by X-ray diffraction analysis of the sample, annealed at the temperature of the beginning of the first crystallization process.