Single crystals of LiNbO3 are grown by the flux method. Measurements are made in the temperature range 20 to 1170 °C of the dielectric constant ϵ, dielectric loss and relative thermal expansion ΔLl/l along the polar axis (the three‐fold axis x3) and perpendicular to the glide plane (x1). A sharp maximum in ϵ corresponding to a decrease in volume is observed in the x3 direction at 1140 °C. This temperature is assumed to be the Curie temperature of LiNbO3 which corresponds to the transition from an electrically ordered state (ferro or ferrielectric, rather than antiferroelectric) into a paraelectrical state. The temperature dependences of ϵ and Δl/l below the Curie temperature show several similar anomalies. Some of these anomalies may be due to phase transitions.

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For specific modification of the fundamental optical and photoelectrical properties of silicon transparent for wavelengths beyond 1.1μm, boron ions have been implanted into n-type wafers at doses of 1 х 1013 cm-2–1 х 1015 cm-2 followed by annealing at 900 °C and 1000 °C (20 min). The IR reflection spectra, Raman spectroscopy and scanning electron microscopy data have been compared with the photosensitivity spectra (1.4–2.2 μm) and with the integrated photoresponse in the IR (1.0–4.1 μm) and UV (0.25–0.4 μm) regions. These studies allow for materials engineering to obtain new data on the influence of defect formation on the optical properties of the material and to evaluate the technological conditions for practical application of the modified material.

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