Alkali ratio control for lead-free piezoelectric thin films utilizing elemental diffusivities in RF plasma

Abstract

High performance piezoelectric thin films are generally lead-based, and find applications in sensing, actuation, and transduction in realms of biology, nanometrology, acoustics, and energy harvesting. Potassium sodium niobate (KNN) is considered to be the most promising lead-free alternative, but is hindered by the inability to control and attain perfect stoichiometry materials in thin film form while using practical large area deposition techniques. In this work, we identify the contribution of elemental diffusivities in radio frequency (RF) plasma in determining alkali loss in KNN thin films. We have also examined the effect of substrate temperature during the RF-magnetron sputtering deposition on the crystal structure of the substrate and KNN thin films, as well as the effect of post-annealing treatments.These results indicate the need for well-designed source materials and the potential to use deposition partial pressures to alter dopant concentrations.

Operando Sodiation Mechanistic Study of a New Antimony-Based Intermetallic CoSb as a High-Performance Sodium-Ion Battery Anode

“…The difference in the full width at half-maximum (fwhm) of Co 2p can be associated with some differences in Co environments. The Na 1s peak appears at 1073 eV, consistent with the reported Na 1s spectra …”

“…The Na 1s peak appears at 1073 eV, consistent with the reported Na 1s spectra. 54 First Charge. Figure S6 shows the Sb 3d spectra of CoSb electrodes upon desodiation (charging).…”

Oxide Scale Sublimation Chemical Vapor Deposition for Controllable Growth of Monolayer MoS2 Crystals

“…Figure 6b compares the X-ray photoelectron spectroscopy (XPS) of MoS 2 before and after the transfer process, where the spectra of Mo 3d, S 2s, S 2p, K 2p, and Na 1s are presented. [40,41] There is almost no difference in the spectra of Mo and S of MoS 2 before and after the transfer process. For both cases, the S 2p 3/2 and 2p 1/2 peaks were located at ≈162.9 and ≈163.9 eV, while the Mo 3d 5/2 , 3d 3/2 , and S 2s peaks were located at ≈229.9, ≈233.2, and ≈227.2 eV, respectively.…”

Donor‐Induced Performance Tuning of Amorphous SrTiO3 Memristive Nanodevices: Multistate Resistive Switching and Mechanical Tunability

“…[ 2,15,42,43 ] The relative concentration of as-grown Ti 3+ species in the oxygen-defi cient a -STO cells is 45%-65% higher than that of stoichiometric cells. [ 43,44 ] Moreover, the presence of oxygen during the sputtering of stoichiometric a -STO oxides facilitates negative ion creation and re-sputtering processes [ 44,45 ] that lead to the creation of misfi t Ti 2+ metallic suboxide species. [ 43,44 ] Moreover, the presence of oxygen during the sputtering of stoichiometric a -STO oxides facilitates negative ion creation and re-sputtering processes [ 44,45 ] that lead to the creation of misfi t Ti 2+ metallic suboxide species.…”

“…a -STO oxides sputtered in pure argon atmosphere develop inherent oxygen vacancies due to heavy Ar + ion bombardment and preferential removal of oxygen atoms in the vacuum system. [ 43,44 ] Moreover, the presence of oxygen during the sputtering of stoichiometric a -STO oxides facilitates negative ion creation and re-sputtering processes [ 44,45 ] that lead to the creation of misfi t Ti 2+ metallic suboxide species. [ 40,46 ] These stationary misfi t species contribute to a greater degradation of the oxide layer during the high-fi eld-forming process.…”