Micro-Raman Analysis of Some As-S-S-Te Nanostructured Semiconductors

Abstract

In the present work some nanostructured chalcogenides of the As-S-Sb-Te system have been investigated by non-contact Micro-Raman spectroscopy which is a powerful technique for obtaining information on the local structure of the crystalline as well as disordered materials, especially when the composition and structure is varied. In this paper we report micro-Raman spectra of As1.17S2.7Sb0.83Te0.40, As1.04 S2.4Sb0.96Te0.60, As0.63S2.7 Sb1.37Te0.30 , and As0.56S2.4Sb1.44 Te0.60, of bulk semiconductor compounds and thin films. These semiconductor alloys are interesting and important from the point of view of assessing their physical properties, primarily the structure, as well as for determining the scope of technical application. It was established that the Raman spectra of light scattering of bulk samples differs from the spectra of thin films with a higher As content and a low Sb content, but samples prepared as bulk and powder exhibit the same behavior. All spectra have characteristic intense bands which are assigned to the Te-Te (ν = 119 cm−1), As-As (ν = 234 cm−1), AsS3/2 (ν = 345 cm−1), As4S4 (ν = 495, 236, 223, 189, 168 cm−1), As4S3 (270–273 cm−1), S8 rings (ν = 146, 220 cm−1) and SbO (ν = 255 cm−1) structural units. It was also found that the sample As0.63S2.7Sb1.37Te0.30 have a more amorphous phase, while As0.56S2.4Sb1.44Te0.60, As1.17S2.7Sb0.83Te0.40 and As1.04S2.4Sb0.96Te0.60 samples are more polycrystalline.