Growth of amorphous TeOx (2≤x≤3) thin film by radio frequency sputtering

Thin films of Tellurium oxide ${\mathrm{TeO}}_{\mathit{x}}$ over a wide range of $x$ (2 to 3) were prepared by radio frequency diode sputtering at room temperature on corning glass and quartz substrate. The deposited films are amorphous in nature and IR spectroscopy reveals the formation of Te-O bond. X-ray photoelectron spectroscopy shows the variation in the stoichiometry of ${\mathrm{TeO}}_{\mathit{x}}$ film from $x=2$ to 3 with an increase in oxygen percentage (25 to 100%) in processing sputtering gas composition. Raman spectroscopy depicts the formation of ${\mathrm{TeO}}_3$ trigonal pyramid besides ${\mathrm{TeO}}_4$ disphenoid in the amorphous ${\mathrm{TeO}}_{\mathit{x}}$ film with increase in the value of $x$ . The varying stoichiometry of ${\mathrm{TeO}}_{\mathit{x}}$ thin film ($x=2$ to 3) was found to influence the optical, electrical, and elastic properties. The optical band gap of film increases from 3.8 to 4.2 eV with increasing $x$ and is attributed to the decrease in density. The elastic constants (${\mathrm{C}}_{11}$ and ${\mathrm{C}}_{44}$ ) of the deposited films are lower than the corresponding value reported for ${\mathrm{TeO}}_2$ single crystal.