On the dielectric constant of titanium dioxide

Conductive rutile TiO2 has received considerable attention recently due to a number of applications. However, the static dielectric constant in conductive, reduced or doped TiO2 appears to cause controversy with reported values in the range 100-10000. In this work, we propose a method for measurements of the dielectric constant in conductive, n-type TiO2 that involves: (i) hydrogen implantation to form a donor profile at a known depth, and (ii) capacitance-voltage measurements for donor profiling. We can not confirm the claims stating an extremely high dielectric constant. On the contrary, the dielectric constant of conductive, reduced rutile TiO2 is similar to that of insulating rutile TiO2 established previously, with a Curie-Weiss type temperature dependence and the values in the range 160-240 along the c-axis.

Large-Size Free-Standing Single-crystal β-Ga2O3 Membranes Fabricated by Hydrogen Implantation and Lift-Off

In this paper, we have demonstrated the large-size free-standing single-crystal β-Ga2O3 NMs fabricated by the hydrogen implantation and lift-off process directly from MOCVD grown β-Ga2O3 epifilms on native substrates. The...

Thin Films of Nanocrystalline Vanadium Dioxide: Modification of the Properties, and Electrical Switching

Vanadium oxide films have been fabricated by the acetylacetonate and triethoxy vanadyl sol-gel methods on silicon substrates, as well as by magnetron sputtering on glass-ceramic substrates. Additional annealing in reducing atmosphere results in formation of vanadium dioxide or mixed phases with a VO2 predominance. The obtained films demonstrate the metal-insulator transition and electrical switching. In the films produced from triethoxy vanadyl, the peculiarities of electrical properties are related to the size effect, heterophase character of vanadium oxide films, and different types of charge carriers in the bulk of nanocrystallites and on their surfaces. Also, the effect of doping with hydrogen by means of plasma-immersion ion implantation on the properties of vanadium dioxide is explored. It is shown that the transition parameters in VO2 thin films depend on the hydrogen implantation dose. At doses exceeding a certain threshold value, the films are metallized, and the phase transition no longer occurs.