Thce results of investigations the effects various defects on the photo and electro- luminescence spectra ( intensity, value of longc wave of luminesce) structures n-ZnO/p-GaN were represented. .

Data for the influence of different defects on the photoluminescence and electroluminescence spectra (emission intensity and wavelength) of n -ZnO/ p -GaN structures are reported.

Abstract The effect of Fe and Mn impurities on the magnetic parameters of ZnO wide-gap semiconductor films produced by high-frequency sputtering with wide variations in the defect concentration is studied. The introduction of Mn and Fe magnetic impurities brings about the existence of a magnetically ordered state in the semiconductor matrix, with different positions of the axis of easy magnetization. In the case of doping with Mn, this axis lies perpendicularly to the film plane, and in the case of doping with Fe, this axis lies in the film plane.

The effect of Fe and Mn impurities on the magnetic parameters of ZnO wide-gap semiconductor films produced by high-frequency sputtering with wide variations in the defect concentration is studied. The introduction of Mn and Fe magnetic impurities brings about the existence of a magnetically ordered state in the semiconductor matrix, with different positions of the axis of easy magnetization. In the case of doping with Mn, this axis lies perpendicularly to the film plane, and in the case of doping with Fe, this axis lies in the film plane.

ZnO films obtained by high-frequency magnetron sputtering and doped with a Fe 57 metallic 3 d impurity by the diffusion method are studied. The type of local environment of Fe 57 impurity atoms on varying the deposition parameters of ZnO films is determined by Mössbauer spectroscopy. It is established that the ground state of Fe 57 impurity atoms corresponds to metallic iron in the magnetically ordered state and there is a small fraction of Fe 57 atoms with a local environment corresponding to the complex oxide Fe 3 O 4 , having the magnetically ordered state; there is also a fraction of iron atoms in the paramagnetic state. The magnetic and magnetooptical parameters of the films were measured using magnetooptic Kerr effect. The spectral dependences of the polar magnetooptic Kerr effect in ZnO(Fe 57 ) films are measured in a photon energy range of 1.5–4.5 eV and simulated by the effective-medium method. It is established that ZnO(Fe 57 ) possess an easy-plane magnetic anisotropy with a magnetization lying in the film plane.

Влияние наночастиц, тонких пленок Ag, Au на генерацию носителей заряда в структурах с множественными квантовыми ямами на

AbstractThe emission spectra of structures based on ZnO films deposited by high-frequency magnetron sputtering are studied. Clearly pronounced emission lines associated with the recombination of free (λ = 363 nm) and bound excitons (λ = 377, 390, 410 nm) are observed in the PL (photoluminescence) spectra ( T = 300 K) of n -ZnO/ p -GaN:Mg structures, and no substantial emission is observed in the impurity PL region λ = 450–600 nm. Only emission lines characteristic of n -ZnO (λ = 374 nm) are observed in the EL (electroluminescence) spectra of n -ZnO/ p -ZnO structures ( T = 300 K).

It has been shown that Ag and Au nanoparticles and thin layers influence charge carrier generation in InGaN/GaN multiple quantum well structures and crystalline ZnO films owing to the surface morphology heterogeneity of the semiconductors. When nanoparticles 10 < d < 20 nm in size are applied on InGaN/GaN multiple quantum well structures with surface morphology less nonuniform than that of ZnO films, the radiation intensity has turned out to grow considerably because of a plasmon resonance with the participation of localized plasmons. The application of Ag or Au layers on the surface of the structures strongly attenuates the radiation. When Ag and Au nanoparticles are applied on crystalline ZnO films obtained by rf magnetron sputtering, the radiation intensity in the short-wavelength part of the spectrum increases insignificantly because of their highly heterogeneous surface morphology.

The emission spectra of structures based on ZnO films deposited by high-frequency magnetron sputtering are studied. Clearly pronounced emission lines associated with the recombination of free (λ = 363 nm) and bound excitons (λ = 377, 390, 410 nm) are observed in the PL (photoluminescence) spectra (T = 300 K) of n-ZnO/p-GaN:Mg structures, and no substantial emission is observed in the impurity PL region λ = 450–600 nm. Only emission lines characteristic of n-ZnO (λ = 374 nm) are observed in the EL (electroluminescence) spectra of n-ZnO/p-ZnO structures (T = 300 K).

AbstractZnO films obtained by high-frequency magnetron sputtering and doped with a Fe^57 metallic 3 d impurity by the diffusion method are studied. The type of local environment of Fe^57 impurity atoms on varying the deposition parameters of ZnO films is determined by Mössbauer spectroscopy. It is established that the ground state of Fe^57 impurity atoms corresponds to metallic iron in the magnetically ordered state and there is a small fraction of Fe^57 atoms with a local environment corresponding to the complex oxide Fe_3O_4, having the magnetically ordered state; there is also a fraction of iron atoms in the paramagnetic state. The magnetic and magnetooptical parameters of the films were measured using magnetooptic Kerr effect. The spectral dependences of the polar magnetooptic Kerr effect in ZnO(Fe^57) films are measured in a photon energy range of 1.5–4.5 eV and simulated by the effective-medium method. It is established that ZnO(Fe^57) possess an easy-plane magnetic anisotropy with a magnetization lying in the film plane.

Уменьшение концентрации дефектов в пленках ZnO, полученных методом высокочастотного магнетронного распыления, дает возможность эффективного легирования акцепторными примесями как в катионной (Li), так и анионной подрешетках (N+) и получение дырочного типа проводимости с воспроизводимыми параметрами (концентрации, подвижности) носителей заряда. Легирование азотом производилось с помощью отжига пленок ZnO в атмосфере высокочастотного газового разряда. В результате измерений с помощью эффекта Холла (методика Ван-дер-Пау) показано, что использование тонких слоев Eu, нанесенных на поверхность ZnO-пленок, приводит к увеличению концентрации и подвижности основных носителей заряда. Введение металлических примесей, отличающихся по размерам ионных радиусов (Ag, Au), в катионную подрешетку пленок ZnO с целью компенсации напряжений несоответствия дает возможность увеличения концентрации центров излучательной рекомбинации. DOI: 10.21883/FTP.2017.05.44411.8437

It is demonstrated that a reduction in the defect concentration in ZnO films formed by high-frequency magnetron sputtering allows effective doping with acceptor impurities both in the cation (Li) and anion (N+) sublattices and p-type conductivity with reproducible charge-carrier parameters (concentration and mobility) to be obtained. ZnO films are doped with nitrogen by annealing in a high-frequency gas discharge atmosphere. Hall measurements by the Van der Pauw technique show that the deposition of thin Eu layers on the ZnO film surface increases the concentration and mobility of majority charge carriers. The embedding of metal impurities with different ionic radii (Ag and Au) in the cation sublattice of the ZnO films to compensate misfit stresses makes it possible to enhance the concentration of radiative-recombination centers.

For ZnO films, nanorods, and bulk single crystals doped with Er+ ions, it is shown that the effect of codopants introduced into the cation and ion sublattices and the observation of a high-intensity emission band at the wavelength λmax = 1535 nm are defined by the local environment of the Er+ ion. Doping of the films and single crystals with Er+ ions by diffusion brings about an infrared (IR) emission band with a low intensity because of an inadequate concentration of impurity ions. The emission intensity of this band can be raised by introducing additional Ag, Au, or N+ impurities into the ZnO films. The UV-emission intensity of the Er-doped films and single crystals at λmax = 368–372 nm is identical to that of the undoped films. ZnO nanorods doped with Er only or together with Al or Ga codopants exhibit only one IR band (at λmax = 1535 nm), whose intensity decreases upon the introduction of codopants. Doping of the nanorods with the N+ gaseous impurity during growth (930 < T < 960°C) and then with the Er+ impurity by diffusion does not yield a substantial increase in the IR-emission intensity compared to the that of the corresponding band for nanorods not doped with the N+ impurity. In the Er-doped nanorods, whose photoluminescence spectra exhibit a high-intensity band at λmax = 1535 nm, the UV emission band at λmax = 372 nm is practically lacking.

The use of Ag impurity in Er-doped ZnO films deposited by AC magnetron sputtering with a low growth rate has increased the emission intensity at λ = 1535–1540 nm. An increase in the deposition rate and in the temperature of substrates, as well as the use of Li and N+ impurities, led to a considerable increase in the intensity of the line with λ = 376–379 nm in the case of doping with rare-earth ions (Er, Tm), which makes it possible to use this semiconductor for creation of devices for the short-wavelength spectral region. Introduction of additional impurities in Er-doped ZnO films deposited on bulk ZnO crystals with increasing deposition rate and temperature caused an increase in the intensity of the line with λ = 1535–1540 nm. The photoluminescence spectra of ZnO films doped with Tm (ZnO) exhibited intense emission of lines with λmax = 377 nm.

Photoinduced defects in a-Si:H films arise due to an increase in the density of midgap states when weak strained silicon–hydrogen (Si–H) bonds transform to dangling Si—Si bonds and also due to the presence of separate regions with different densities and types of Si—H bonds. In rare-earth-doped InGaN/GaN multiple quantum well structures, defects are induced as a result of increasing the luminescence excitation intensity in taking microphotoluminescence spectra. This complicates the spatial relief of the random potential mainly in the lateral plane and may result in clustering, with In content in the clusters differing from the mean value, and even precipitation of the InN and GaN phases.

The effect of the Er3+-ion excitation type on the photoluminescence spectra of crystalline ZnO(ZnO〈Ce, Yb, Er〉) films is determined in the cases of resonant (λ = 532 nm, Er3+-ion transition from 4S3/2, 2H11/2 levels to 4I15/2) and non-resonant (λ = 325 nm, in the region near the ZnO band-edge emission) excitation. It is shown that resonant excitation gives rise to lines with various emission intensities, characteristic of the Er3+-ion intracenter 4f transition with λ = 1535 nm when doping crystalline ZnO films with three rare-earth ions (REIs, Ce, Yb, Er) or with two impurities (Ce, Er) or (Er, Yb), independently of the measurement temperature (T = 83 and 300 K). The doping of crystalline ZnO films with rare-earth impurities (Ce, Yb, Er) leads to the efficient transfer of energy to REIs, a consequence of which is the intense emission of an Er3+ ion in the IR spectral region at λmax = 1535 nm. The kick-out diffusion mechanism is used upon the sequential introduction of impurities into semiconductor matrices and during the postgrowth annealing of the ZnO films under study. The crystalline ZnO films doped with Ce, Yb, Er also exhibit intense emission in the visible spectral region at room temperature, which makes them promising materials for optoelectronics.

The effects of the parameters of ZnO-film deposition onto different substrates using the method of ac magnetron sputtering in a gas mixture of argon and oxygen hare studied. The phenomenon of self-organization is observed, which leads to invariability of the surface morphology of the ZnO films upon a variation in the substrate materials and deposition parameters. The parameters of the macro- and micro-photoluminescence spectra of the films differ insignificantly from the parameters of the photoluminescence spectra of bulk ZnO crystals obtained by the method of hydrothermal growth. The presence of intense emission with a narrow full-width at half-maximum (FWHM) in different regions of the spectrum allows ZnO films obtained by magnetron sputtering doped with rare-earth metal impurities (REIs) to be considered as a promising material for the creation of optoelectronic devices working in a broad spectral range. The possibility of the implementation of magnetic ordering upon legierung with REIs significantly broadens the functional possibilities of ZnO films. The parameters of the photoluminescence spectra of ZnO nanorods are determined by their geometrical parameters and by the concentration and type of the impurities introduced.

Measurements of the microphotoluminescence (microPL) spectra of InGaN/GaN:Sm and InGaN/GaN:Eu quantum well (QW) structures show that the action of a magnetic field gives rise to Van Vleck paramagnetism for Eu 3+ and Sm 3+ . The macrophotoluminescence (macroPL) spectra recorded after measuring the microPL spectra of InGaN/GaN QW structures doped with Sm or Eu + Sm at a high excitation level (>10 23 photons cm −2 s −1 ) in magnetic fields contain no QW emission lines which are present in the macroPL spectra recorded before these microPL measurements. This is indicative of the presence of photoinduced defects. Annealing of the InGaN/GaN:Sm and InGaN/GaN:(Eu + Sm) structures reduces the concentration of photoinduced defects.

This paper presents the results of complex measurements of the microphotoluminescence spectra of quantum-well structures based on InGaN/GaN〈Sm〉 and the determination of the concentration and charge state of the Sm dopant. It has been shown that an increase in the magnetic field strength and the excitation intensity of the microphotoluminescence spectra leads to an increase in the luminescence intensity and a shift in the position of the maximum of the emission wavelength toward the short-wavelength region of the spectrum. Measurements of the microphotoluminescence spectra with variations in the external magnetic field strength, as well as with the introduction of paramagnetic and magnetic impurities, provide additional information on the mechanisms of formation of luminescence spectra in the quantum-well structures InGaN/GaN〈Sm〉,〈Eu + Sm〉. In the long-wavelength region, the influence of the magnetic field on the shape of the microphotoluminescence spectra of the InGaN/GaN structures doped with Sm and Sm + Eu is less pronounced than that in the short-wavelength region.