Lithium silicon phosphorus oxynitride (LiSiPON) thin films with different compositions have been prepared by RF magnetron sputtering in N2 by using three targets xLi2SiO3 · (1 − x) Li3PO4 with x = 0.1, 0.3, and 0.5. Compared with LiPON, the electrical properties of LiSiPON have been improved by introducing silicon. LiSiPON films deposited from the target 0.5Li2SiO3 · 0.5Li3PO4 yield the highest ionic conductivity of up to 9.7 × 10−6 S cm−1 with an activation energy of only 0.41 eV. The main mechanism for increasing ionic conductivity is the enhancement of carrier mobility. By DC polarization measurements the electronic partial conductivity was found at least seven orders of magnitude smaller than the ionic conductivity. Linear voltammetry results showed that the LiSiPON films are electrochemically stable in contact with stainless steel in the voltage range of 0–6 V. The substitution of silicon for phosphorus in the film evidenced from X‐ray photoelectron spectroscopy analysis indicated silicon in the film will create more abundant cross‐linking structures Si–O–P and (P, Si)–N < (P, Si), hence created more Li+ conducting paths which favored the higher mobility of lithium ions and larger ionic conductivity. The optical bandgap was found to decrease with increasing silicon content. We demonstrate that the prepared LiSiPON films with their larger ionic conductivity and low electronic conductivity may serve as an alternative to LiPON for applications in high energy density and high voltage lithium batteries.

Diffusion-controlled electrodeposition was investigated experimentally and by finite element method simulations of the concentration profile on microstructured band electrode arrays (MEA) and compared to existing theoretical approaches. The simulations revealed the establishment of a diffusion layer significantly larger than anticipated according to existing models for individual bands. The electrochemical depositions were simulated by extending the finite element method to allow the modeling of changing electrode geometries during growth by use of automated remeshing steps. As an ideal case of electroplating, thin films of copper electrodeposited onto MEA of gold on SiO 2 /Si wafers were studied as a benchmark system. The electrodeposition of ZnO on MEA following initial reduction of O 2 served as an example of a multi-step reaction. The simulations considered an increasing depletion of the reactant (O 2 in the case of ZnO, Cu 2+ in the case of Cu) toward the electrode bands and film growth limited by mass transport. The growth of experimentally observed dendrites and even their detailed size distribution over the whole array was precisely predicted by the simulations. An extended understanding of diffusion-controlled growth could be achieved and used to study the temporal development of electrochemical depositions, applicable also in complex geometries.

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Chromogenic thin films are crucial building blocks in smart windows to modulate the flux of visible light and heat radiation into buildings. Electrochromic materials such as tungsten oxide are well established in those devices. Sputter deposition offers a well-suited method for the production of such layers, which can also be used on an industrial scale. Tungsten oxide films were prepared by means of reactive ion-beam sputter deposition. The choice of distinct gas mixtures as well as the growth temperature during the sputtering process allows to tune the properties of the resulting layers. Especially, the variation in the growth temperatures was found to have an impact on the structure of the resulting samples and, as a consequence, on their optical and electrochemical properties. By specific choice of the reactive gas, the deposition of colorless transparent as well as blue films of different composition is possible. The optical transmittance in the visible spectral range was up to 75% for as-deposited oxygen-rich layers. Additionally, hydrogen-doped tungsten oxide samples were grown. Superior electrochromic switching was observed for H$$^{+}$$ + -doped layers, probably by some kind of preconditioning. This resulted in a value for the standardized optical coloration efficiency of 26.5 cm$$^{2}$$ 2 /C.

Interdigitated microstructured electrode arrays of gold or silver bands were used as substrates for the electrodeposition of crystalline ZnO thin films under pulsed galvanostatic conditions from aqueous Zn(NO 3 ) 2 solutions. For current densities below the limiting current density, homogenous films of ZnO were obtained as proven by scanning electron and confocal laser microscopy. For current densities greater than those limited by the diffusion of Zn 2+ and NO 3 − , strongly dendritic structures were formed. Film growth was analyzed based on the duplex diffusion layer model. The influence of convective diffusion was directly observed when only one set of electrode bands was polarized during deposition. By use of an underlying gate electrode in the substrate, field-effect measurements were performed to electrically characterize the samples.