The nanometer films of bismuth selenide: Deposition, chemical analysis and nano-morphology by complementary instrumental analysis

Bismuth selenide Bi2Se3 is a 2D semiconductor of interest to optoelectronics, quantum thermo-electronics and computing. We studied composition and structure of Bi2Se3 films of 5 nm to 100 nm made by magnetron sputtering on sapphire and mica. XRD yields a crystalline phase and nanocrystal size. Raman spectra of Bi₂Se₃ by two lasers (2.33 and 1.58 eV) show characteristic vibrations: A1g1 (out-of-plane) at 69.3 cm-1, Eg2 (in-plane) at 127.0 cm-1 and A1g2 (out-of-plane) at 170.3 cm-1. The linearly polarized Raman spectra in horizontal-horizontal and horizontal-vertical modes were collected. Area ratios of Eg2 and A1g1 peaks was analyzed vs. film thickness, and the trend correlates with that for preferential in-plane vs. vertical growth of the related material. The complementary AFM provides an additional detail. The combination of structural and advanced spectroscopic methods is powerful in the studies of structure, composition, and morphology of quantum nanomaterials.