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

Abstract

Thin films of Tellurium oxide TeOx 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 TeOx 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 TeO3 trigonal pyramid besides TeO4 disphenoid in the amorphous TeOx film with increase in the value of x. The varying stoichiometry of TeOx 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 (C11 and C44) of the deposited films are lower than the corresponding value reported for TeO2 single crystal.

Er3+-doped fluorotellurite thin film glasses with improved photoluminescence emission at 1.53 µm

“…1, n F is slightly smaller than n B (~3 % at 1500 nm). This behavior has been previously observed for other thin films glasses fabricated by PLD [26,28,37] or TeO x films produced by rf-sputtering [35] and it has been attributed to a reduction of the glass density. This is likely related to the decrease of the kinetic energy of the laser generated species that reach the substrate and the incorporation of oxygen to the growing film during the deposition process, as it has been previously observed in either oxide or oxyfluoride tellurite thin film glasses, such (Table I).…”

“…Moreover, the observation of well-defined interference fringes in the experimental transmission spectrum (Fig. 1) evidences the deposition of homogeneous thin films [24,35] with a large refractive index contrast with respect to the substrate (n SiO2 ≈ 1.44 at 1.53 µm). The structure of film glasses is characterized by an increase on the relative concentration of [TeO 3 ] groups and a decrease of the glass network connectivity with respect to the bulk glass that is evidenced by the increase of the I C /I B ratio and the decrease of the area of band associated to the vibration of symmetric Te-O-Te linkages (band A in Fig.…”

“…However, the presence of oxygen rich defects is unlikely to occur in tellurite glasses. A third alternative would be a further oxidation the cations, which in our case should be related to the oxidation of tellurium from Te +4 to Te +6 , as it has been observed in tellurium oxide thin films produced by rf-sputtering [35].…”

“…Thus, we have investigated their composition, structure and morphology. [35]. Thus, XPS and Raman analysis have been performed to clarify the chemical nature of the glasses and the effect of the excess of oxygen on the glass structure.…”

Laser-induced grayscale patterning in TeOx thin films

“…Tellurium suboxide (TeO x ) [15,16], one of the chalcogenide phase change material [17,18], has been extensively investigated and used in both scientific and industrial applications, such as digital laser recording media [15,19], due to its excellent storage ability, high sensitivity and resolution, and low fabrication cost. The as-deposited TeO x film in vacuum actually consists of Te metal micrograins usually with diameters that are less than 2 nm and embedded in an amorphous TeO 2 matrix of a special granular structure [20][21][22][23].…”