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Taking zinc selenide (ZnSe) crystals as an example, a procedure of determination of the main parameters of traps is proposed. At first, the conductivity type (electron or hole one) in a crystal of phosphor at its excitation is determined with the help of photoelectric studies or studies of the thermionic emission or thermal or photo-thermal emf. Then the energy of the thermal electron delocalization is determined, e.g., by using the method of thermally stimulated luminescence with sequential fractional heating. As a result, the frequency factors of corresponding traps are found as well. Knowing the effective electron mass, it is easy to calculate the effective density of electron states in the conduction band. Finally, the cross sections of the free-electron localization and their temperature dependences can be determined for all traps from a simple equation., На прикладi кристалiв селенiду цинку (ZnSe) запропонована система визначення основних параметрiв пасток. Спочатку за допомогою фотоелектричних дослiджень, або дослiджень термоемiсiйного струму, або термо- i фототермо-ерс, визначають характер провiдностi (електронний чи дiрковий) в кристалофосфорi при збудженнi. Далi визначаються енергiї термiчної делокалiзацiї електронiв, наприклад, методом послiдовного фракцiйного нагрiвання термостимульованої люмiнесценцiї. При цьому також визначаються частотнi фактори для вiдповiдних пасток. Знаючи ефективну масу електрона легко вираховується ефективна густина станiв електронiв у зонi провiдностi. I в результатi з простого рiвняння можна визначити перерiзи локалiзацiї вiльних електронiв на усi пастки та їх температурнi залежностi.

The luminescence spectra of high-resistance ZnSe crystals consist of two main bands with maxima at 630 nm (1.92 eV) and 970 nm (1.28 eV). The planned comparison has been carried out between the spectra of X-ray luminescence and photoluminescence of ZnSe among themselves in the spectral region from 400 to 1200 nm at different excitation intensities and different temperatures (8, 85, 295, and 420 K). It is found that the forms of luminescence bands do not depend on the excitation intensities. The band form with a maximum at 970 nm also does not depend on the excitation type, and the band at 630 nm differs slightly under the X-ray and UV excitations. The temperature dependences of the spectral positions of bands’ maxima and their half-widths are analyzed. A conclusion is drawn that the 970-nm emission band is elementary. A short-wavelength shift of the spectral maximum of the 630-nm band with increasing the temperature makes it possible to conclude that this luminescence band is non-elementary. This correlates with the previously discovered feature of this band related to the realization of two recombination mechanisms (electron and hole) at this luminescent center., Спектри люмiнесценцiї високоомних кристалiв ZnSe складаються з двох основних смуг з максимумами при 630 нм (1,92 еВ) i 970 нм (1,28 еВ). Проведено порiвняння спектрiв рентгенолюмiнесценцiї i фотолюмiнесценцiї ZnSe мiж собою в спектральної областi вiд 400 до 1200 нм при рiзних iнтенсивностях збудження i при рiзних температурах (8, 85, 295 i 420 К). Встановлено, що форми смуг свiчення не залежать вiд iнтенсивностей збудження. Форма смуги з максимумом при 970 нм також не залежить вiд типу збудження, а смуга 630 нм – трохи вiдрiзняється при рентгенiвському i УФ-збудженнi. Проаналiзовано температурнi спектральнi положення максимумiв смуг i їх пiвширини. Зроблено висновок про елементарностi смуги свiтiння 970 нм. Короткохвильове змiщення спектрального максимуму смуги 630 нм при збiльшеннi температури дозволяє зробити висновок про неелементарнiсть цiєї смуги свiтiння. Це корелює з ранiше виявленою особливiстю цiєї смуги про реалiзацiю двох механiзмiв рекомбiнацiї (електронному та дiрковому) на цьому центрi свiтiння.

The luminescence spectra of UO22+ molecular ions absorbed on the surface of disperse SiO2 were investigated when excited by X-rays or light. It has been established that the efficiency of these luminophors is determined by the type and structure of the adsorption complexes (AC) formed. Various AC cause many elementary luminescence spectra that were detected by means of selective laser spectroscopic methods. It has been established that uranyl ions are linked to the surface by water molecules; H2O molecules coordinate uranium in water-uranyl complexes and take part in the formation of adsorption bonds. Two types of AC corresponding to physical and chemical adsorption states were observed. We believe that complexes of the first type are fixed on surface hydroxyls by hydrogen bonds. The chemisorbed complexes are formed by interaction of water molecules, creating water-uranyl complexes with surface silicon, bridging oxygen atoms, and surface structural defects. The emission spectra under X-ray excitation are the result of energy transfer to chemisorbed complexes by elementary excitation. The efficiency of energy transmission depends on the presence of surface water molecules which are effective non-radiative recombination centers. The effect of heat pretreatment (20–1000°C) on the luminescence properties was also investigated. The sample preparation technique was optimized to obtain highly effective X-ray transformers. These systems are characterized by high stability to radiation and heat. It is shown that luminophors based on SiO2UO22+ systems may be used as luminescence detectors and transformers of ionizing radiation.

The photoluminescence (PL), roentgenoluminescence (RL), and optical absorption of ZnSe were measured near the fundamental edge in the temperature range from 80 to 400 K. Because of the much smaller absorption coefficient for x-rays as compared to visible light, the contribution to RL from emitting centers located deeper in the sample is higher. The quality of ZnSe can be assessed by correlating its near-edge PL and RL spectra. The temperature dependences of the peak positions of the blue PL and RL bands indicate that these emissions are due to the same center. The blue RL band is redshifted by 18 meV in comparison with PL, and its intensity is lower than that of the longer wavelength bands. The different positions of the PL and RL bands are interpreted in terms of thermal spike formation under x-ray excitation and reabsorption of the emitted light.