Investigation of surface defects in BaTiO3 nanopowders studied by XPS and positron annihilation lifetime spectroscopy

Enhancing Photodetection Ability of MoS2 Nanoscrolls via Interface Engineering

“…232.2 and 229.2 eV in the high-resolution spectrum (Figure a) correspond to Mo 3d 3/2 and Mo 3d 5/2 energy level peaks, respectively, while S 2p 3/2 and S 2p 1/2 energy level peaks (Figure b) are located at 163.2 and 162 eV, respectively; these positions indicate that the MoS 2 phase is of high purity with a Mo valence state of +4, which is consistent with the MoS 2 systems in previous works. , The split of barium 3d orbits (3d 5/2 and 3d 3/2 ) into two states is observed in Figure c; for simplicity, these can be defined as phases α and β . The more intensive components emerging at 793.8 and 778.5 eV stem from Ba 2+ states in the perovskite structure (BaO moiety), primarily corresponding to phase α, while the other components with an upshift of 1.6 eV represent the β phase. , Two characteristic peaks for Ti 2p level emerging at 457.9 eV (Ti 2p 3/2 ) and 463.8 eV (Ti 2p 1/2 ) imply the chemical state of Ti is 4+ (Ti 4+ ) . On the other hand, the presence of additional shoulder peaks on the low-binding energy side can be attributed to Ti 3+ state. , The shift of Ti valence from Ti 4+ to Ti 3+ is relative to the defects, for example, the oxygen vacancies (Figure S2b).…”

“…37 The more intensive components emerging at 793.8 and 778.5 eV stem from Ba 2+ states in the perovskite structure (BaO moiety), primarily corresponding to phase α, while the other components with an upshift of 1.6 eV represent the β phase. 38,39 Two characteristic peaks for Ti 2p level emerging at 457.9 eV (Ti 2p 3/2 ) and 463.8 eV (Ti 2p 1/2 ) imply the chemical state of Ti is 4+ (Ti 4+ ). 40 On the other hand, the presence of additional shoulder peaks on the low-binding energy side can be attributed to Ti 3+ state.…”

Piezotronic Effect Induced Schottky Barrier Decrease to Boost the Plasmonic Charge Separation of BaTiO3-Au Heterojunction for the Photocatalytic Selective Oxidation of Aminobenzyl Alcohol

“…The two doublets of Ba 4d suggest the presence of at least two chemical states of Ba. The lower BE doublet (blue shadow) can be related to the α-phase BTO; while the higher BE one (green shadow) can be attributed to the β-phase BTO portion or other components, such as BaCO 3 and Ba­(OH) 2 on the surface. , XPS analysis confirms the coexistence of the key elements in the BTO-Au nanohybrids.…”

Tuning Bienenstock–Cooper–Munro learning rules in a two-terminal memristor for neuromorphic computing

“…The reduction in oxygen vacancies is consistent with the shift of Ba 3d and Ti 2p to the high binding energy direction after annealing. 45,46…”

“…The reduction in oxygen vacancies is consistent with the shift of Ba 3d and Ti 2p to the high binding energy direction after annealing. 45,46 Because the concentration reduction of oxygen vacancies by annealing is from XPS analysis, the initial conductance and synaptic potentiation and depression effects are supposed to be strongly affected. Thus, the conductance is measured after annealing under the same conditions with the as-prepared device with various series resistances.…”