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Optical Diagnostics of Laser Evaporation of CuInS2 Polycrystalline Compound
Abstract
In the radiation spectrum of the erosion laser plasma of CuInS2 polycrystalline compound, the presence of resonance spectral lines of CuIn and InI is revealed, as well as of spectral lines which correspond to cascade transitions and of lines from the displaced terms of the copper atom. No intense radiation of positive ions is observed in the spectral range from 200 to 600 nm. The binding energies of Cu–S, In–S, Cu–Cu, In–In, and Cu–In atoms, as well as atomic and orbital bond orders of the CuInS2 cluster, are calculated by the Hueckel pseudoempirical method within the valent approximation. It is found that In(1, 3) atoms inversely centering the lower faces of cations Cu(6, 6
I), as well as cations Cu(4, 4
I) and In(5, 5
I) centering the lateral faces of the crystal, do not form strong bonds in the structure. Therefore, in the evaporation processes they must easily evolve from the structure of the CuInS2 chalcopyrite crystal and make a predominant contribution to the radiation spectrum of laser plasma. From the standpoint of energy, the atoms of sulfur and nodal atoms of copper evaporate mainly in the form of combined complexes of CuS molecules. One can assume that the initial growth layers will be obtained with a deficiency in sulfur and with substantial violation of their stoichiometry and the structure of the initial compound.
... At air pressures of 13.3 and 103.3 kPa, spectral lines of atoms and ions of the products of the electrode material and the decay of air molecules in plasma were observed against the background of broadband emission of aluminum oxide nanostructures and continuous radiation, which may be due to thermal and recombination radiation of the plasma. As follows from [27], copper and indium atoms are the least bound in the chalcopyrite molecule, so the line part of the emission spectrum is due mainly to individual spectral lines of atoms and singly charged ions of copper and indium, the same as for the gas-discharge plasma based on atmospheric pressure air [20]. The emission spectrum of the gas component was more pronounced at atmospheric air pressure and consisted mainly of intense bands of the second positive system of the nitrogen molecule in the spectral range of 280-390 nm, which is typical for the diffuse stage of the [9] as well as of individual spectral lines N1 and N11, which were often observed in the emission spectra of a spark discharge in air [28]. ...
... [14] Over the past few decades, various deposition techniques have established to deposit CIS materials both by chemical as well as physical method. Few of the chemical methods includes: chemical bath deposition (CBD), [15,16] spray pyrolysis, [17][18][19][20] electrodeposition, [21,22] successive ionic layer adsorption and reaction SILAR, [23,24] etc. and co-evaporation from elemental source, [25] molecular beam epitaxy, [26] Rfsputtering, [27] chemical vapor deposition (CVD), [28] laser chemical vapor deposition (LCVD), [29] atomic layer deposition, [30] etc. are the physical methods. ...
... Polycrystalline CIS laboratory solar cell has been produced with an efficiency at almost 13 percent. [18] The CIS thin films can be deposited by chemical methods such as chemical bath deposition (CBD), [19][20][21] spray pyrolysis, [22,23] electrodeposition, [24,25] successive ionic layer adsorption and reaction (SILAR) [26,27] as well as physical method like co-evaporation from elemental source, [28,29] molecular beam epitaxy, [30,31] sputtering, [32,33] chemical vapor deposition (CVD), [34,35] laser chemical vapor deposition (LCVD), [36] atomic layer deposition, [37] etc. Although the deposition of thin films via the aforementioned physical methods results in good-quality thin films, it is highly expensive and requires many material targets. ...
... The spectral lines of atoms and ions are observed against a continuous background of plasma radiation, which may be associated with the thermal radiation of plasma or with the plasma recombination radiation. As was shown in work [10], the copper and indium atoms are least strongly bound in the chalcopyrite molecules composing the massive electrodes. Therefore, the linear component of the plasma radiation spectrum is predominantly associated with separate spectral lines of atoms and singly charged ions of copper and indium both in the case of laser plasma formed at the target surface under vacuum conditions [11,12] and in the case of atmosphericpressure gas-discharge plasma [13]. ...
... The spectral lines of atoms and ions are observed against a continuous background of plasma radiation, which may be associated with the thermal radiation of plasma or with the plasma recombination radiation. As was shown in work [10], the copper and indium atoms are least strongly bound in the chalcopyrite molecules composing the massive electrodes. Therefore, the linear component of the plasma radiation spectrum is predominantly associated with separate spectral lines of atoms and singly charged ions of copper and indium both in the case of laser plasma formed at the target surface under vacuum conditions [11,12] and in the case of atmosphericpressure gas-discharge plasma [13]. ...
The characteristics of the nanosecond overvoltage discharge ignited between semiconductor electrodes based on the CuInSe2 chalcopyrite compound in the argon and nitrogen atmospheres at gas pressures of 5.3–101 kPa are reported. Due to the electrode sputtering, chalcopyrite vapor enters the discharge plasma, so that some CuInSe2 molecules become destroyed, whereas the others become partially deposited in the form of thin films on solid dielectric substrates located near the plasma electrode system. The main products of the chalcopyrite molecule decomposition in the nanosecond overvoltage discharge are determined; these are atoms and singly charged ions of copper and indium in the excited and ionized states. Spectral lines emitted by copper and indium atoms and ions are proposed, which can be used to control the deposition of thin chalcopyrite films in the real-time mode. By numerically solving the Boltzmann kinetic equation for the electron energy distribution function, the electron temperature and density in the discharge, the specific losses of a discharge power for the main electronic processes, and the rate constants of electronic processes, as well as their dependences on the parameter E/N, are calculated for the plasma of vapor-gas mixtures on the basis of nitrogen and chalcopyrite. Thin chalcopyrite films that effectively absorb light in a wide spectral interval (200–800 nm) are synthesized on quartz substrates, by using the gas-discharge method, which opens new prospects for their application in photovoltaic devices.
... This may be due to the thermal radiation of the plasma or its recombination radiation. As it is shown in [11], copper and indium atoms are the least bound in the chalcopyrite molecule, which is a constituent of massive electrodes. Therefore, the linear part of the plasma emission spectrum is predominantly due to separate spectral lines of atoms and singly charged copper and indium ions. ...
The features of an over-voltage high-current nanosecond discharge in argon of high pressure (р=202 kPa) ignited between the electrodes of CuInSe 2 compound are presented. In the sputtering of massive chalcopyrite electrodes, the CuInSe 2 pair gets into the discharge plasma. Main products of dissociation of chalcopyrite molecules in the over-voltage nanosecond discharge are established. They were in excited and ionized states and in the spectra of plasma radiation they were predominantly represented by atoms and single charged ions of copper and indium. It is proposed to use the spectral lines of copper and indium to control the process of thin films of chalcopyrite deposition in a real time. Using gas-discharge method thin films of chalcopyrite are synthesized on quartz substrates. These films effectively absorb the radiation falling on their surface in the spectral range of 200-800 nm. This property opens the prospects for their application in photovoltaic devices
Приведено оптичнi характеристики i параметри перенапруженого наносекундного розряду в аргонi мiж електродами з алюмiнiю i халькопiриту (СuInSe2) при p(Ar) = 13,3 і 101 кПа. Внаслiдок мiкровибухiв природних неоднорiдностей на робочих поверхнях електродiв в сильному електричному полi в плазму вносяться як пари алюмiнiю, так I пари халькопiриту, що створює передумови для синтезу за межами розряду тонких плiвок четверного халькопiриту – CuAlInSe2. Дослiджено iмпульси напруги i струму на розрядному промiжку величиною d = 1 · 10−3 м (розмiри наведено в системi СI), а також iмпульсний енергетичний внесок у плазму. Ретельно дослiджено спектри випромiнювання плазми, що дозволило встановити основнi продукти розпаду молекули халькопiриту та енергетичнi стани атомiв i однозарядних iонiв алюмiнiю, мiдi i iндiю, в яких вони утворюються в розрядi. Виявлено репернi спектральнi лiнiї атомiв I iонiв алюмiнiю, мiдi i iндiю, якi можуть бути використанi для контролю за процесом напилення тонких плiвок четверного халькопiриту. Методом числового моделювання параметрiв плазми перенапруженого наносекундного розряду на основi парiв алюмiнiю i халькопiриту, шляхом розв’язку кiнетичного рiвняння Больцмана для функцiї розподiлу електронiв за енергiями розраховано температуру i концентрацiю електронiв у розрядi, питомi втрати потужностi розряду на основнi електроннi процеси i константи швидкостi електронних процесiв в залежностi вiд величини параметра E/N (де E – напруженiсть електричного поля, N – загальна концентрацiя сумiшi парiв алюмiнiю та аргону).
The review article presents the characteristics and parameters of an overstressed nanosecond discharge (OND) in air and argon at atmospheric pressure between electrodes made of zinc, copper, and aluminium. The technique, methods and experimental conditions for studying the characteristics and parameters of the OND and its application for the synthesis of thin nanostructured films of transition-metal oxides synthesized under intense ultraviolet (UV) irradiation of the substrate with film are presented. The microexplosions of inhomogeneities on the surface of electrodes in a strong electric field act as a source of metal vapour in plasma. The spatial, electrical, and optical characteristics of the OND in air and argon between transition-metal electrodes, which was ignited in the needle-to-needle electrode system, are reported. The results of experimental measurements of the parameters of the discharge plasma based on the Cu–air gas–vapour mixtures are presented. The optical characteristics of thin nanostructured transition-metal oxide films synthesized under conditions of automatic UV irradiation of the substrate by the discharge plasma are considered.
A convenient and low cost technology was employed to prepare copper indium disulfide thin films, which can be analogous to other chalcogenides. The designed precursor solutions with Cu/In ratio at 1.5:1, 1:1, and 1:1.5, respectively, were prepared and coated on the glass substrate by dip-withdrawing method. The thin films were characterized by XRD, SEM, UV–Vis–NIR spectrophotometer, NKD-7000W spectrophotometer, Raman microscope and wavelength dispersive XRF spectrometer. As a result, chalcopyrite-type CuInS2 is the dominant phase in final products. CuxS is also obtained as a minor phase composition. The as-prepared CuInS2 films are of high absorption coefficient of 2.65 × 105 cm−1 at 400 nm and 1.7 × 105 cm−1 at 600 nm. The calculated band gap values are 1.28–1.62 eV, according with the theoretical band gap of CuInS2.
The aim of the paper is to describe a facility for spectral analysis of nonstationary emission spectra. It permits to investigate the composition and state of emitting fragments of plasma of multicomponent compounds and to measure the excited particle density in the plasma. The block diagram and main performances of the facility are presented.
The paper deals with the investigation of the radiation of an erosion plasma formed as a result of interaction between laser radiation with a duration of 20 ns, intensity of (3–5) × 108W/cm2, and wavelength of 1.06 µm and aluminum and indium obstacles. The photoelectric technique is used to record radiation spectra from different spatial zones of the laser jet in the range from 210 to 600 nm. The dynamics of laser jet radiation on individual transitions of aluminum and indium atoms and ions are investigated, as well as the distribution of effective radiation fluxes from different excited levels of aluminum and indium atoms. It is demonstrated that excited Al and In atoms and InII ions are formed in this plasma. The dielectronic recombination reaction in the plasma core of the laser jet proceeds over the course of trec= 800 ns (AlII), 25 ns (InIII), and 180 to 360 ns (InII). The average propagation velocity of the laser jet is 6 to 8 km/s. The obtained results are of interest from the standpoint of performing optical diagnostics of laser-induced plasma of aluminum- and indium-containing crystals, as well as for comparison with the results of numerical simulation of the characteristics of laser-induced plasma on the basis of metals of group III.