CdS Nanocrystallines: Synthesis, Structure and Nonlinear Optical Properties

We report the synthesis, structure and nonlinear optical properties of cadmium sulphide (CdS) nanocrystallines (NCs) synthesized electrochemically both with and without detergent ATLAS G3300. Relevant structural and morphological features are explored by X-ray diffraction and scanning electron microscopy (SEM) techniques. The efficiency of the second harmonic generation (SHG) appears to be strongly dependent on the energy density of the incident fundamental laser radiation and NC sizes.Comment: 2020 IEEE 15th International Conference on Advanced Trends in Radioelectronics, Telecommunications and Computer Engineering (TCSET), Conference Location: Lviv-Slavske, Ukraine, 25-29 February 2020, 5 pages, 8 figures, 3 table

Photoinduced Absorption and Birefringence Changes in Complex Chalcogenide Crystals AgxGaxGe1-xSe2 (0,167 ≤ x ≤ 0,333)

Четвертинні монокристали AgxGaxGe1-XSe2 (х = 0,333, 0,250, 0,200 і 0,167) були вирощені методом Стокбаргера Бріджмена. Досліджено спектральні залежності фотоіндукованого поглинання в нелегованих кристалах селеніду при опроміненні лазерними імпульсами з довжиною хвилі 808 нм. Представлено динаміку фотоіндукованого оптичного поглинання AgGaGe3Se8:Cu під вливом 532 нм та 1300 нм лазерного випромі- нювання CW.; Quaternary crystals AgxGaxGe1- XSe2 (x = 0.333, 0.250, 0.200 and 0.167) were grown by Bridgman Stockbarger. Spectral dependence of photoinduced absorption in undoped selenide crystals irradiated laser pulses with a wavelength of 808 nm. The dynamics of photoinduced optical absorption AgGaGe3Se8: Cu at 532 nm poured and 1300 nm laser CW. The changes of the birefringence demonstrate substantial changes of time kinetics depending on the pumping wavelengths. It was found that the changes of the photoinduced birefringence are at least 4 times higher for the 532 nm pumping wavelength with respect to the 1300 nm wavelength. The Ag cations, Cu dopants and local trapping levels play here crucial role

Photoelectric Properties of AgGaGeS4 Crystal

У роботі досліджено кінетику релаксації фотопровідностів в монокристалі AgGaGeS4 Установлено, що час релаксації фотопровідності в кристалах AgGaGeS4 залежить від інтенсивності освітлення та температури. Оцінено глибину залягання пастки. ; Kinetics of photoconductivity relaxation in AgGaGeS4 crystal has been investigated in this work. It has been established that photoconductivity relaxation time in AgGaGeS4 crystals depends on light intensity and the temperature. The depth of trap has been estimated from the experimental data

A Novel Effect of CO2 Laser Induced Piezoelectricity in Ag2Ga2SiS6 Chalcogenide Crystals

We have discovered a substantial enhancement of the piezoelectric coefficients (from 10 to 78 pm/V) in the chalcogenide Ag2Ga2SiS6 single crystals. The piezoelectric studies were done under the influence of a CO2 laser (wavelength 10.6 μm, time duration 200 ns, lasers with power densities varying up to 700 MW/cm2). Contrary to the earlier studies where the photoinduced piezoelectricity was done under the influence of the near IR lasers, the effect is higher by at least one order, which is a consequence of the phonon anharmonic contributions and photopolarizations. Such a discovery allows one to build infrared piezotronic devices, which may be used for the production of the IR laser tunable optoelectronic triggers and memories. This is additionally confirmed by the fact that analogous photoillumination by the near IR laser (Nd:YAG (1064 nm) and Er:glass laser (1540 nm)) gives the obtained values of the effective piezoelectricity at of least one order less. The effect is completely reversible with a relaxation time up to several milliseconds. In order to clarify the role of free carriers, additional studies of photoelectrical spectra were done

Two-photon absorption of Tl

Novel materials for the infrared two-photon absorption — Tl1-xIn1-xSnxSe2 single crystals (x = 0.1,0.2) were grown. Two-photon absorption (TPA) was studied at CO2 laser wave-length 9.4μm with pulse duration 1μs. The studies were performed at different temperatures and for the nanocrystallite sizes varying within the 7–200 nm. The studies have shown that the TPA may be enhanced during the decrease of the nanocrystallite sizes below 50–60 nm. There exists also some critical x value at which the TPA value begin substantially to increase. The studied nanocrystallites are relatively stable to the infrared laser treatment and are not hygroscopic which allow to use them in different IR optoelectronic devices

Study of Photo and Heat Induced Piezoelectric Effect in Monocrystals AgxGaxGe1-хSe2

У монокристалах AgGaGe3Se8 було досліджено фотоіндукований п’єзоелектричний ефект. Зроблено виміри залежності п’єзоелектричних модулів від температури та визначено п’єзооптичний коефіцієнт. Проана- лізовано внесок різних механізмів у фотостимульовані п’єзоелектричні механізми.; Photoinduced piezoelectric effect in monocrystals AgGaGe3Se8 was found under the influence of continuos irradiation of a laser with wavelength of 523 nm. The changes relatively the main diagonal of piezocurrent components d11, d22, d33 been studied. To study the contribution of thermal and photo-stimulated piezooptic effect made measurements of depending piezoelectric modules on temperature and determined piezooptic coefficient. Analyzed contribution of different mechanisms of photoinduced piezoelectric mechanisms

Preparation and photoelectric properties of solid solutions Tl1−x In1−x Sn x Se 2 (х = 0–0,25)

Розроблено технологічні умови вирощування монокристалів твердих розчинів Tl1-x In1-x Sn x Se 2 (х = 0–0,25). Рентгенівським методом порошку розшифровано кристалічну структуру сплавів й запропоновано механізм утворення твердого розчину. Досліджено спектральний розподіл фотопровідності отриманих кристалів при T = 300 K та термостимульовану провідність. Показано вплив катіонного заміщення In 3+ на Sn 4+ у твердих роз-чинах Tl 1-x In1-x Sn x Se 2 (х = 0–0,25) на їх кристалографічні та фотоелектричні властивості. ; he technological conditions for growth of solid solutions Tl 1-x In1-x Sn x Se 2 (х = 0–0,25) single crystals have been developed. The crystal structure of the alloy has been solved by X ray diffraction powder method, the mechanism of the solid solution formation is proposed. Spectral distribution of photoconductivity for obtained crystals at T= 300 K and thermoinduced conductivity have been studied. The effect of In 3+ for Sn 4+ cationic substitution in solid solutions Tl 1-x In1-x Sn x Se 2 (х = 0–0,25) on their crystallographic and photovoltaic properties is shown

Preparation and Electric Properties of Solid Solutions Tl1-xIn1-xSnxS2 (х=0 – 0,5).

Розроблено технологічні умови вирощування монокристалів твердих розчинів Tl1-xIn1-xSnxS2 (х=0 – 0,5). Рентгенівським методом порошку розшифрована кристалічна структура сплавів і запропоновано механізм утворення твердого розчину. Досліджено температурну залежність питомої темнової електропровідності, виз- начено енергії активації провідності. ; The technological conditions for growth of solid solutions Tl1-xIn1-xSnxS2 (х=0 – 0,5) single crystals have been developed. The crystal structure of the alloy has been solved by X ray diffraction powder method, the mechanism of the solid solution formation is proposed. The temperature dependence of the specific electrical dark conductivity and the activation energy of conductivity have been determined

Two-photon absorption of Tl 1-x

Novel materials for the infrared two-photon absorption — Tl1-xIn1-xSnxSe2 single crystals (x = 0.1,0.2) were grown. Two-photon absorption (TPA) was studied at CO2 laser wave-length 9.4μm with pulse duration 1μs. The studies were performed at different temperatures and for the nanocrystallite sizes varying within the 7–200 nm. The studies have shown that the TPA may be enhanced during the decrease of the nanocrystallite sizes below 50–60 nm. There exists also some critical x value at which the TPA value begin substantially to increase. The studied nanocrystallites are relatively stable to the infrared laser treatment and are not hygroscopic which allow to use them in different IR optoelectronic devices

Novel Quaternary TlGaSn2Se6 Single Crystal as Promising Material for Laser Operated Infrared Nonlinear Optical Modulators

The studies of the laser operated third order nonlinear optical features of novel TlGaSn2Se6 crystal were done. The main efforts were devoted to a search of a possibility to apply these crystals as laser operated optoelectronic material. For this reason, the third harmonic generation of the Nd:YAG pulse laser 1064 nm as the fundamental beam with varied energy density of up to 200 J/m2 was studied. As a source of laser operated light, we have used the cw laser (532 nm), exciting the material above the energy gap. Additionally, the influence of middle-energy Ar+ ions on the XPS spectra of the TlInSn2Se6 surface has been explored. We have shown that the main contribution of the Se4p states is manifested in the upper part of the valence band of TlInSn2Se6 We have established that for the TlGaSn2Se6 crystal there exists a possibility of variation of the third harmonic generation efficiency using illumination by external continuous wave laser beam. The discovered effect makes it possible to utilize TlGaSn2Se6 crystal in advanced optoelectronic laser operated devices