Structural analysis of RF sputtered Ge-Sb-Se thin films by Raman and X-ray photoelectron spectroscopies

Abstract

International audienceChalcogenide thin films (GeSe2)100 − x(Sb2Se3)x (with x = 10 and 50) were deposited by Radio-frequency (RF) magnetron sputtering. In order to study the impact of Ar pressure on the structure and the composition of selenide thin films structural properties of thin films and targets were investigated by means of Raman scattering spectroscopy and X-ray photoelectron spectroscopy (XPS). Under low pressure (5 · 10− 3 mbar), the increase of wrong bonds like Ge(Sb)-Ge(Sb) was confirmed by Raman and also XPS for both composition. The observed structural changes with Ar pressure are linked with modification of the composition of the selenide films analyzed by EDS and XPS. Furthermore for higher Ar pressure (5 · 10− 2 mbar), RF sputtered thin film and target structure present a great similarity. These differences driven by Ar pressure modification are probably related to distinctive sputtering rate and mean free path of the particles ejected from target for the different Ar pressure

Investigation of the Atomic Structure of Ge-Sb-Se Chalcogenide Glasses

“…The atomic parameters support the formation of Getetrahedral and Sb-trigonal units in Ge 40 Se 60 glass structure. When the Sb content gradually increases, strong Sb units are formed with light influence of the tetrahedral Ge network, which causes only negligible changing of the partial pair distribution functions, coordination numbers, and bondangle distributions.…”

Amorphous Ge‐Sb‐Se thin films fabricated by co‐sputtering: Properties and photosensitivity

“…Weak band usually ascribed to Se–Se bending mode vibrations was found at ~136 cm −1 . Low‐intensity Raman band found in stoichiometric Sb 2 Se 3 films at ~249 cm −1 , assigned to Se–Se bond stretching vibrations in short selenium chains, shifts toward higher wave numbers with increasing Ge concentration .…”

“…51 Weak band usually ascribed to Se-Se bending mode vibrations was found at~136 cm À1 . 10 Low-intensity Raman band found in stoichiometric Sb 2 Se 3 films at 249 cm À1 , assigned to Se-Se bond stretching vibrations in short selenium chains, shifts toward higher wave numbers with increasing Ge concentration. 8 For Sb-rich samples, the low-intensity Raman band with maximum at 159 cm À1 can be connected with Sb-Sb homopolar bonds' vibrations in the Se 2 Sb-SbSe 2 units.…”

“…Although the Ge‐As‐Se system is particularly attractive due to its greater glass‐forming region compared to Ge‐Sb‐Se system, the introduction of antimony provides higher polarizability increasing (non)linear refractive index and reduction in photosensitivity, representing an interesting option for nonlinear optics . Last but not least, improved shaping ability of Ge‐Sb‐Se glasses allows fabrication of fibers or thin films, which are of high importance considering optical sensor development, for instance . This is why study of thin films of ternary Ge‐Sb‐Se system have already attracted the attention of many authors …”

“…[7][8][9] Last but not least, improved shaping ability of Ge-Sb-Se glasses allows fabrication of fibers or thin films, which are of high importance considering optical sensor development, for instance. [10][11][12] This is why study of thin films of ternary Ge-Sb-Se system have already attracted the attention of many authors. [13][14][15][16][17][18] It is well-known that the exposure to the light or other radiation that excites electron-hole pairs, enables to produce some structural changes in chalcogenide glasses and amorphous films.…”