A photonic crystal microcavity with the tunable Q factor has been implemented on the basis of a bound state in the continuum using the advanced liquid crystal cell technology platform. It has been shown that the Q factor of the microcavity changes from 100 to 360 in the voltage range of 0.6 V.

Copper-doped titanium oxynitride (TiN x O y ) thin films were grown by atomic layer deposition (ALD) using the TiCl 4 precursor, NH 3 , and O 2 at 420 °C. Forming gas was used to reduce the background oxygen concentration and to transfer the copper atoms in an ALD chamber prior to the growth initiation of Cu-doped TiN x O y . Such forming gas-mediated Cu-doping of TiN x O y films had a pronounced effect on their resistivity, which dropped from 484 ± 8 to 202 ± 4 μΩ cm, and also on the resistance temperature coefficient (TCR), which decreased from 1000 to 150 ppm °C−1 . We explored physical mechanisms causing this reduction by performing comparative analysis of atomic force microscopy, X-ray photoemission spectroscopy, X-ray diffraction, optical spectra, low-temperature transport, and Hall measurement data for the samples grown with and without forming gas doping. The difference in the oxygen concentration between the films did not exceed 6%. Copper segregated to the TiN x O y surface where its concentration reached 0.72%, but its penetration depth was less than 10 nm. Pronounced effects of the copper doping by forming gas included the TiN x O y film crystallite average size decrease from 57−59 to 32−34 nm, considerably finer surface granularity, electron concentration increase from 2.2(3) × 10 22 to 3.5(1) × 10 22 cm −3 , and the electron mobility improvement from 0.56(4) to 0.92(2) cm 2 V −1 s −1 . The DC resistivity versus temperature R(T) measurements from 4.2 to 300 K showed a Cu-induced phase transition from a disordered to semimetallic state. The resistivity of Cu-doped TiN x O y films decreased with the temperature increase at low temperatures and reached the minimum near T = 50 K revealing signatures of the quantum interference effects similar to 2D Cu thin films, and then, semimetallic behavior was observed at higher temperatures. In TiN x O y films grown without forming gas, the resistivity decreased with the temperature increase as R(T) = − 1.88T 0.6 + 604 μΩ cm with no semimetallic behavior observed. The medium range resistivity and low TCR of Cu-doped TiN x O y make this material an attractive choice for improved matching resistors in RF analog circuits and Si complementary metal−oxide−semiconductor integrated circuits.

Mode hybridization is a unique way to manipulate the mode inside a fixed cavity or at interface. For example, Tamm plasmon-polariton at solid interface can be spectrally shifted without tuning the interface. Experimental implementation of tunable hybrid Tamm-microcavity modes is reported. The hybrid modes are excited in a one-dimensional photonic crystal bounded with a gold layer by attaching a nematic liquid crystal microcavity. Coupling between Tamm plasmon-polariton and microcavity modes leads to repulsion of their dispersion curves controlled by the refractive index of a liquid crystal and the polarization of incident light. Effective tuning of hybrid modes through heating or applying an external electric field to the liquid crystal layer is demonstrated. The experimentally measured strength coupling value between Tamm and microcavity modes was 20.7 meV.

Using the Hall effect measurements, it is established that the sign of carriers in the LuxMn1–xS solid solutions changes upon temperature and concentration variations. The extrema in the temperature dependence of the electrical resistance and hysteresis of the electric polarization are found. The change in the sign of the exchange coupling between the nearest neighbors under electron doping is established. The magnetoresistance in the paramagnetic region is caused by the change in the induced electric polarization in a magnetic field.

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