Radiation thermopiles are structural units of sensors used for measuring the energetic parameters of radiation in the wavelength range from 0.1 to 100 µm. The question of the application...

The peculiarities of obtaining p-Bi_0.5Sb_1.5Te₃ and n-Bi₂Te_2.7Se_0.3 thin thermoelectric films with a thickness of about 300 nm grown on a polyimide substrate by the pulsed-laser-deposition method are reported. The influence of the growth temperature, pressure and target-to-substrate distance on the film’s thermoelectric properties is investigated. Thermoelectric p- and n-type films exhibit a high Seebeck coefficient of 220 and –200 μV/K and low electrical power factors of 9.7 and 5.0 μW/(cm K²) respectively due to the relatively high electrical resistances of the films.

Correlation between hardness and optical properties of diamond-like carbon (DLC) coatings is considered. Various methods for the characterization of mechanical, chemical and optical properties of DLC coatings are used; however, some of these methods are destructive, and others are non-destructive. It was found that optical properties of DLC coatings are proportional to their hardness. The mathematical expression that allows to calculate the hardness of a DLC coating according to its refractive index is proposed. Therefore, it is possible to avoid the use of destructive methods (such as nano-indentation technique) to characterize DLC coatings.

In this article, we report on experimental studies of the influence of several laser radiation parameters, such as the duration of the laser pulse, the radiation wavelength, and the pulse energy, on the efficiency of the destruction of urinary calculi. The study used a laser lithotripter based on a fiber Tm laser generating at a wavelength of 1940 nm with pulses with a duration of about 1800 μs and pulse energy of up to 6 J, as well as a femtosecond solid-state Yb laser generating at a wavelength of 1032 nm with a pulse duration of about 250 fs and pulse energy of up to 400 μJ. A comparative analysis was carried out according to such criteria as the productivity of lasers when removing a unit mass of images and the amount of sample displacement resulting from the retropulsion effect. The results obtained in this work demonstrated that the femtosecond laser loses approximately two times its efficiency in terms of sample material removal. However, this shows the absolute advantage of the photoionization mechanism of femtosecond laser ablation in the study of retropulsion and thermal heating, which were completely absent in this case.

Thermoelectric materials in the form of thin films are used to create a wide variety of sensors and devices. The efficiency of these devices depends on the quality and efficiency of the thermoelectric materials obtained in the form of thin films. Earlier, we demonstrated that it is possible to obtain high-performance Bi₂Te₃Sb_1.5 films less than 1 μm thick on polyimide substrates by using the PLD method, and determined optimal growth conditions. In the current work, the relationship between growth conditions and droplet fraction on the surface, microstructure, grain size, film thickness and chemical composition was studied. A power factor of 5.25 μW/cm×K² was achieved with the reduction of droplet fraction on the film surface to 0.57%. The dependencies of the film thickness were studied, and the effect of the thickness on the efficiency of the material is shown. The general trend in the growth dynamics for Bi₂Te₃Sb_1.5 films we obtained is the reduction of crystalline size with Pressure-Temperature (PT) criterion. The results of our work also show the possibility of a significant reduction of droplet phase with simultaneous management of crystalline features and thermoelectric efficiency of Bi₂Te₃Sb_1.5 films grown on polyimide substrates by varying growth conditions.

Radiation thermopiles are basic structures for sensors used for measuring energy parameters of different radiation with wavelength from 0.1 to 100 mcm. Current work describes features of using p-Bi0.5Sb1.5Te3 and n-Bi2Te2.7Se0.3 thin film thermopiles obtained with pulsed laser deposition method on different substrates. Thermal modeling and experimental research reveal the possibility of achieving responsivity of 1 V/W and time constant of 10 seconds with the use of polyimide substrates and absorption zone of 16 mm in diameter