## 3 Interfacial Phenomena between Solid-State Electrolytes and Electrodes
### Deposition Techniques
#### 3.1.1 Physical Deposition Methods  
One of the most common physical deposition techniques is thermal evaporation owing to its simplicity. This technique is utilized in multiple applications such as memory-switching applications [257; 258] and solar cells [259]. In particular, this method is commonly applied to the fabrication of anode materials for LIBs [260; 261]. In a vacuum chamber, a solid material is heated to a temperature that produces a vapor pressure sufficient to raise a vapor cloud inside the vacuum chamber [262]. Then, these evaporated particles are free to traverse the chamber and stick to a substrate as a film. The deposition materials can be pure atomic elements including metals, oxides and nitrides. The thickness, uniformity and adhesion strength of the film can be adjusted by controlling a number of deposition parameters such as voltage, pressure and substrate temperature. Two main heating sources--resistive filament and electron beam (e-beam) are widely used for heating the source material. Depending on the temperature required for evaporating the material, resistive filament heating is generally used for the materials with the evaporation temperature below 1500 \({}^{\circ}\)C, in contrast to the e-beam heating for the materials with the evaporation temperature above 1500 \({}^{\circ}\)C [262].  
Pulsed laser deposition (PLD) which is a widely used method for growing epitaxial thin films consists of a target holder and a substrate holder housed in a vacuum chamber (Figure 8). A high-power laser is used as an external energy source to vaporize materials and to deposit thin films. A set of optical components are used to focus and raster the laser beam over the target surface. The decoupling of the vacuum hardware and the evaporation power source makes this technique so flexible that it is easily adaptable to different operational modes without the constraints imposed by the use of internally powered evaporation sources. In PLD, a pulsed-laser beam rapidly ablates oxide from a solid ceramic disc target to form an energetic plasma plume, which then propagates and condenses onto a substrate that is held at a particular temperature. Generally speaking, the target determines the composition of the thin film, but the codeposition of different targets is possible to create a new composition of the film [263]. In addition, a single target composition can be used to create films of different stoichiometry due to the coupling between target composition, PLD chamber pressure, laser fluence, substrate temperature and the resultant film composition. Compared to other deposition techniques, PLD can provide unique advantages--stoichiometric transfer of materials, capability for reactive deposition in ambient gases, growth of two-dimensional nanostructures, growth of multilayered epitaxial heterostructures, high  
target surface, the sputter deposition process will occur. There are several types of sputtering systems including direct current (DC) sputtering, radio frequency (RF) sputtering and magnetron sputtering. The DC and RF sputtering systems are used for sputtering conductive materials and non-conductive materials, respectively [266]. As the magnetron sputtering system can increase the sputtering rate, combined sputtering systems, i.e., DC magnetron and RF magnetron are widely used for the fabrication of thin films.