Title: Summary Thin Films

Choose the correct statement.

- The production of thin films results in perfect crystalline materials, the possibility of designing new materials through layer-by-layer growth and changing the properties of existing materials. (correct)
- The production of thin films is mostly used for depositing amorphous films a determined material on a substrate, with a controlled thickness, mainly for device architecture applications.

- The main methods for thin film deposition are Pulsed Layer Deposition (PLD) and Molecular Beam Epitaxy (MBE). (correct)
- The main methods for thin film deposition are Pulsed Beam Epitaxy (PBE) and Molecular Layer Deposition (MLD).

- In Pulsed Layer Deposition (PLD), a high power pulsed laser ablates a target of a polycrystalline sample of the material that is to be deposited. (correct)
- In Pulsed Layer Deposition (PLD), a solid elemental target is evaporated via resistive heating, which will then be deposited on a substrate, previously activated using a pulsed laser.

- In Molecular Beam Epitaxy (MBE), different solid elemental targets are evaporated via resistive heating. The differenet beams may be generated simultaneously or separately, providing a high control on the stoichiometry along the film. (correct)
- In Molecular Beam Epitaxy (MBE), a plasma plume is formed after the reaction of the evaporated elemental target with the ozone present in the vacuum chamber. The products of the reaction are then deposited on the substrate as a thin film.

- An epitaxial film has a well-defined orientation relative to the substrate, whereas in a coherent film the unit cells of the deposited film and the substrate are matched across the interface. (correct)
- In an epitaxial film the unit cells of the deposited film and the substrate are matched across the interface, whereas a coherent film has a well-defined orientation relative to the substrate.

- Strain can be induced in thin films by depositing them on substrates with a different lattice constant. Depending on the relative mismatch, the strain can be compressive or tensile. (correct)
- Strain can be induced in thin films by using isotopes of the atoms, which present a different atomic radius.

- Strain accomodation may occur by changing bond lengths, bond angles and/or by point defect formation. (correct)
- Strain accomodation may occur by tilts, rotations, Jahn-Teller distortions and/or by point defect formation.

- Anion vacancy involves a local expansion of the lattice film and therefore is favoured by tensile strain. Analogously, cation vacancy is favoured by compressive strain. (correct)
- Cation vacancy involves a local expansion of the lattice film and therefore is favoured by tensile strain. Analogously, anion vacancy is favoured by compressive strain.

- The Glazer notation is a useful way to describe the pattern of octahedral rotations in the perovskite structure. (correct)
- The Glazer notation is a useful way to describe the pattern of octahedral tilts in the perovskite structure.

- Distortions induced by strain may lead to new properties, for example in europium titanate, lanthanum aluminate and bismuth ferrite. (correct)
- Distortions induced by strain may lead to new properties, for example in europium aluminate, lanthanum ferrite and bismuth titanate.