Effect of annealing on properties and performance of HfO/SiO optical coatings for UV-applications.

The field of ultraviolet (UV)-laser applications is currently experiencing rapid growth in the semiconductor processing, laser micromachining and biomedical markets. Key enablers for these technologies are optical coatings used to manipulate and guide laser beams in a targeted manner. As laser power, laser fluence and pulse frequencies increase, the demands on the physical properties of the coating materials become more stringent.

van der Waals epitaxy of highly (111)-oriented BaTiO on MXene.

We report on the high temperature thin film growth of BaTiO3 on Ti3C2Tx MXene flakes using van der Waals epitaxy on a degradable template layer. MXene was deposited on amorphous and crystalline substrates by spray- and dip-coating techniques, while the growth of BaTiO3 at 700 °C was accomplished using pulsed laser deposition in an oxygen rich environment. We demonstrate that the MXene flakes act as a temporary seed layer, which promotes highly oriented BaTiO3 growth along the (111) direction independent of the underlying substrate.

Controlling the phase transition in nanocrystalline ferroelectric thin films via cation ratio.

Traditionally, the ferroelectric Curie temperature can be manipulated by chemical substitution, e.g., in Ba1-xSrxTiO3 as one of the archetypical representatives.

Evidence of extended cation solubility in atomic layer deposited nanocrystalline BaTiO thin films and its strong impact on the electrical properties.

Thin films of ≈50 nm thickness with Ba/Ti-ratios ranging from 0.8 to 1.06 were prepared by depositing alternating layers of Ba(OH)2 and TiO2.

Formation of BiFeO from a Binary Oxide Superlattice Grown by Atomic Layer Deposition.

We report on the growth of polycrystalline BiFeO thin films on SiO /Si(001) and Pt(111) substrates by atomic layer deposition using the precursors ferrocene, triphenyl-bismuth, and ozone. By growing alternating layers of Fe O and Bi O , we employ a superlattice approach and demonstrate an efficient control of the cation stoichiometry. The superlattice decay and the resulting formation of polycrystalline BiFeO films are studied by in situ X-ray diffraction, in situ X-ray photoelectron spectroscopy, and transmission electron microscopy.