Orthorhombic Ta3-xN5-yOy thin films grown by unbalanced magnetron sputtering: The role of oxygen on structure, composition, and optical properties

Indirect bandgap, optoelectronic properties, and photoelectrochemical characteristics of high-purity Ta3N5 photoelectrodes

“…A similar bulk composition was previously reported for sputtered Ta 3 N 5 films. 27 These chemical changes in the bulk agree with the changes in surface composition determined by XPS, which reveal an increase of the N/Ta ratio to ∼1.7 and a systematic decrease of the O/Ta ratio to ∼0.2 with increasing annealing temperature ( Table 1 ). Compared to ERDA, the measured O/Ta ratios by XPS are significantly higher due to the formation of a thin surface oxide layer from air exposure.…”

Characterizing Density and Spatial Distribution of Trap States in Ta3N5 Thin Films for Rational Defect Passivation

“…The surface composition of neat films was characterized by XPS (Figure ). The core lines of Ta 4f 7/2 and Ta 4f 5/2 can be observed at 25.25 and 27.16 eV, respectively; the position and splitting of 1.9 eV is consistent with those measured for Ta 3 N 5 films reported in the literature. − The broader doublet with peaks at 25.94 and 27.85 eV can be ascribed to a tantalum oxynitride species (TaO x N y ) with y > x . The N 1s peak associated with Ta 3 N 5 is observed at 396.72 eV and in agreement with those reported in the literature. , The broad peak observed at slightly higher binding energies around 403 eV has been attributed to the Ta 4p 3/2 of tantalum oxide and is again indicative of a mixed species at the surface. , Characterizing the O 1s spectrum measured and fit for the neat films, the peak corresponding to lattice-incorporated oxygen (TaO x N y ) is observed at 530.70 eV while those generally assigned to either −OH or adsorbed H 2 O at the surface of films are measured at 531.95 and 533.30 eV, respectively .…”

“…7 The N 1s peak associated with Ta 3 N 5 is observed at 396.72 eV and in agreement with those reported in the literature. 29,31 The broad peak observed at slightly higher binding energies around 403 eV has been attributed to the Ta 4p 3/2 of tantalum oxide and is again indicative of a mixed species at the surface. 3,32 Characterizing the O 1s spectrum measured and fit for the neat films, the peak corresponding to lattice-incorporated oxygen (TaO x N y ) is observed at 530.70 eV while those generally assigned to either −OH or adsorbed H 2 O at the surface of films are measured at 531.95 and 533.30 eV, respectively.…”

“…7 This has been used to determine the surface of neat films have a composition of N/Ta = 1.42, O/Ta = 0.63, and (O+N)/Ta = 2.05, consistent with the well-reported formation of TaO x N y on the surface of Ta 3 N 5 materials and the surface-sensitive nature of XPS measurements. [7][8][9][10]31 Density and Distribution of Defects in Ta 3 N 5 Thin Films. Synthesized Ta 3 N 5 thin films were then studied by DLCP to resolve the spatial and energetic distribution of trap states throughout the films in an effort to inform our approach to improve material quality (Figure 3).…”