A study was carried out on sputtering yields for PbX (X = S, Se, Te) single crystals with (100) orientation and PbTe and PbSe single-crystal films with (111) orientation under ion-plasma bombardment with argon ions. The PbX single crystals were grown by the vertical zone melting method and oriented along the [100] growth axis. Single-crystal films of lead chalcogenides 2–4 μm thick with an orientation (111) relative to the normal to the substrate were formed by molecular beam epitaxy on silicon substrates. The surface treatment was carried out in a high-density argon plasma reactor of a high-frequency inductive discharge (13.56 MHz) of low pressure at an average ion energy of 50, 100, 150, and 200 eV. Based on the comparative analysis of sputtering rates, it was shown that for the (100) orientation, the sputtering yields for lead telluride were lower compared to lead sulfide and lead selenide. The sputtering yields for PbTe and PbSe for the (111) crystallographic orientation was found to be higher compared to (100) orientation.

The formation of porous Pb nano-and microstructures on the surface of PbTe films during low-energy ion-plasma treatment has been studied using scanning electron microscopy (SEM) combined with machine learning-based image analysis. PbTe epitaxial films with (111) crystallographic orientation were exposed to argon plasma at an ion energy approximately 25 eV for varying durations (60-240 s). SEM imaging at a tilt angle of 70 degrees enabled three-dimensional size estimation of the formed structures, which, together with automated image processing using the DLgram01 deep learning service, allowed for precise calculation of particle number, area, height, and volume. In this paper, a comparative analysis of the parameters of the Pb structure on the surface of lead telluride films with the orientation (111) and PbTe single crystals with the orientation (100) is carried out. This study demonstrates the effectiveness of machine learning for quantitative analysis of surface nanostructures after low energy argon plasma treatment of PbTe surface.

Raman scattering spectra of 1-2 μm thick n-PbS(111) epitaxial films grown by molecular beam epitaxy on BaF2(111) substrates were obtained and analyzed. The spectra were recorded at a low excitation level of 0.36 mW/μm2, which did not cause photo- and thermal degradation of the films. It is shown that, in accordance with the symmetry selection rules, the bands in the spectra correspond to overtone or combination tones of phonon modes of PbS at special points of the Brillouin zone. The analysis of the bands of oxides and oxysulfates of lead, which can mask the bands of lead sulfide, was carried out. The obtained data were used in the analysis of the recorded Raman scattering spectra by epitaxial films of a ternary solid solution PbS0.5Se0.5. Keywords: Raman scattering, low excitation level, photooxidation, epitaxial films, lead sulfide, lead sulfide-selenide.

The article studies the modification of the surface of Pb0.4Sn0.6 Te epitaxial films during ion-plasma treatment in argon plasma. Lead-tin telluride films with a thickness of 2 mu m were grown on BaF2 (111) substrates by molecular beam epitaxy. Ion-plasma treatment was carried out in a dense argon plasma of a high-frequency inductive discharge at an ion energy of similar to 140 eV. The duration of the process is 60 and 120 s. The parameters of an ensemble of nanocones are studied, the evolution of the height of the cones, their lateral dimensions and surface density is described while maintaining the processing time.

In this work, the optical properties of nanocrystalline CdS films in the initial state and after ion-plasma treatment have been studied. The chemical bath deposition technique was used to prepare CdS films with thickness 80-115 nm on glass substrates. The ion-plasma treatment was carried out in argon plasma in a high-density low-pressure radio frequency inductively coupled plasma reactor at an argon ion energy of 25 eV for 30-50 s. It has been established that ion-plasma treatment leads to a decrease in film thickness by 10-15% of the initial one and the formation of new nanostructures on its surface. The results showed that the sizes of coherent scattering regions during plasma treatment decreased for a series of studied samples from 8.2-10.0 nm to 6.3-7.7 nm. This led to an increase in the band gap energy of the for nanocrystalline CdS films from 2.53-2.78 eV to 2.95-3.11 eV.

In the present study, the effect of annealing and Ar-plasma treatment on structural, morphological and optical properties of thermally evaporated β -In 2 S 3 thin films has been investigated. During Ar-plasma treatment, some interesting results were observed that an array of metallic indium nanostructures was formed over In 2 S 3 film surface with quasi-spherical or spread droplet shapes of an average size of 20–100 nm in the lateral direction and a height of less than 70 nm. Here, the Ar-plasma treatment serves as a new strategy for the self-formation of metallic indium nanostructures over the film surface. Further, the optical absorption of In 2 S 3 films has been enhanced from 10 4 to 10 7 cm −1 while the optical band gap energy decreased from 2.71 eV to 2.50 eV after Ar-plasma treatment. The metallic nanostructures loaded on semiconductor surface can act as an electron trap that can effectively prevent the recombination of photo-generated electron-hole pairs.

The effect of ion-plasma treatment on the physical properties of the surface of GaTe crystals is investigated. Gallium telluride crystals were grown by vertical zone melting under the pressure of an inert argon gas of 10.0 MPa at a temperature of 1000 °C and a zone displacement velocity of 9 mm/hr. The treatment was carried out in argon plasma in a high-density low-pressure radio frequency (RF) inductively coupled plasma reactor at an argon ion energy of 100-200 eV for 15-120 s. Using scanning electron microscopy methods, it was shown that the formation of nano- and submicron structures of various architectures (nanohillocks, nanocones, droplet structures) occurred on the surface during processing. It is shown that the sputtering processes are accompanied by enrichment of the near-surface layer with metal atoms and a decrease in oxygen content. The formation of nano- and submicron gallium droplets on the surface has been proved by X-ray diffractometry. The analysis of the raman scattering spectra showed a decrease in the oxide phases of tellurium after plasma treatment. It is established that modification of the GaTe surface leads to suppression of specular optical reflection in the range of 0.4-6.2 eV.

The effect of ion-plasma treatment on the physical properties of the surface of GaTe crystals is investigated. Gallium telluride crystals were grown by vertical zone melting under the pressure of an inert argon gas of 10.0 MPa at a temperature of 1000 o C and a zone displacement velocity of 9 mm/hr. The treatment was carried out in argon plasma in a high-density low-pressure radio frequency (RF) inductively coupled plasma reactor at an argon ion energy of 100-200 eV for 15-120 s. Using scanning electron microscopy methods, it was shown that the formation of nano- and submicron structures of various architectures (nanohillocks, nanocones, droplet structures) occurred on the surface during processing. It is shown that the sputtering processes are accompanied by enrichment of the near-surface layer with metal atoms and a decrease in oxygen content. The formation of nano- and submicron gallium droplets on the surface has been proved by X-ray diffractometry. The analysis of the Raman scattering spectra showed a decrease in the oxide phases of tellurium after plasma treatment. It is established that modification of the GaTe surface leads to suppression of specular optical reflection in the range of 0.4-6.2 eV. Keywords: gallium telluride, ion-plasma treatment, nanostructures, X-ray diffractometry, Raman scattering, reflection spectra.

The formation of Janus-like particles of Pb-Sn during ion-plasma treatment of the surface of lead-tin telluride films was found. Pb0.6Sn0.4Te films 2 mu m thick were grown on (111) BaF2 substrates by molecular beam epitaxy. The ion-plasma treatment of the samples was carried out in a high-density low-pressure radio frequency inductively coupled plasma at an ion energy of 75 eV and 25 eV. The duration of the sputtering process was 240 s. The evolution of the film surface morphology and the formation of Pb-Sn Janus particles with nano-and submicron sizes have been studied.

Raman scattering spectra of 1-2 µm thick n-PbS(111) epitaxial films grown by molecular beam epitaxy on BaF2(111) substrates were obtained and analyzed. The spectra were recorded at a low excitation level of 0.36 mW/µm2, which did not cause photo- and thermal degradation of the films. It is shown that, in accordance with the symmetry selection rules, the bands in the spectra correspond to overtone or combination tones of phonon modes of PbS at special points of the Brillouin zone. The analysis of the bands of oxides and oxysulfates of lead, which can mask the bands of lead sulfide, was carried out. The obtained data were used in the analysis of the recorded Raman scattering spectra by epitaxial films of a ternary solid solution PbS0.5Se0.5.

The paper discusses the physical aspects of surface modification of Pb 1-x Sn x Te (x = 0.00-0.80) epitaxial films during ion-plasma treatment in argon plasma. Lead–tin telluride films 1−2 μm thick were grown on (111) BaF 2 substrates by molecular beam epitaxy. The ion-plasma treatment of the samples was carried out in a high-density low-pressure radio frequency (RF) inductively coupled plasma at an ion energy of 75 eV. The duration of the process is 240 s. The evolution of the surface morphology of the films and the formation of micro- and nanostructures at different ratios of lead and tin are studied.

The processes of surface modification of epitaxial films of lead-tin telluride Pb1 – xSnxTe (х = 0.0–1.0) during ion-plasma treatment in argon plasma at an ion energy of ~25 eV are studied. Films 1–2 µm thick are grown by molecular-beam epitaxy on (111) BaF2 substrates. The treatment is carried out in the dense argon-plasma reactor of a low-pressure RF inductive discharge. It is found that the sputtering rate of Pb1 – xSnxTe decreases as the Sn content in the film increases. It is shown using scanning electron microscopy that nanostructures of various shapes are formed on their surface during sample processing. The size and shape of the nanostructures depend on the tin content in the film and on the plasma-treatment time t (60–240 s). At х = 0.0 and 0.2, hemispherical formations appear on the surface of the sample, the sizes of which increase with treatment time. At t > 120 s, two groups of quasi-spherical particles, differing in size, are formed on the surface. Large particles with a size of 250–500 nm are hollow and, in terms of chemical composition, consisted mainly of lead. When treating films with a high tin content (x = 0.8), an ensemble of vertical nanorods grow on their surface according to the “vapor–liquid–crystal” mechanism up to 30 nm in height with spherical “caps” 20–30 nm in diameter.

Indium sulfide (In 2 S 3 ) is a wide bandgap semiconductor, which is widely used as a window/buffer layer in thin film solar cell applications. In 2 S 3 thin films were deposited using thermal evaporation technique and were annealed in sulfur ambient at 200 °C and 250 °C. Further, these films were treated in inductively coupled argon plasma sputtering with an average argon ion energy of 75 eV for 30 s. The paper presents the effect of Ar-plasma treatment on structure, elemental composition, morphology and topography of In 2 S 3 films and the results were reported. Further, the optimized In 2 S 3 layers were continued for plasma etching process with an average argon ion energy of 25 eV to study the effect of plasma etching duration on the growth of metallic indium nanoparticles over the film surface and the results were discussed in detail.

In this work, the impact of the plasma treatment, during the formation of nanostructure arrays on the surface of the Cu(In,Ga)Se2 films on glass substrates, on the conductivity of the films both in the lateral direction and in the direction normal to the substrate surface was studied. The initial Cu(In,Ga)Se2 films with the Ga/(In + Ga) ratio in the range of 0.03–0.12 were obtained by thermal selenization process of stacked metallic precursors and by co-evaporation of all elements from various sources. The plasma treatment was carried out in a high-density low-pressure RF inductively coupled plasma reactor in argon plasma. The average ion energy was 200 eV, the processing time was 60 s. It is shown that the processes of the plasma nanostructuring of the Cu(In,Ga)Se2 film surface lead to the formation of a thin modified near-surface layer with a resistivity of 2–3 orders of magnitude less than for the bulk of the film.

In this work, we report a novel approach to the surface nanostructuring of lead tin telluride films using inductively coupled argon plasma treatment with the average ion energy of 200 eV and the duration of 20–60 s. The nanostructuring was carried out on the plasma treated surface of epitaxial single-crystal Pb1−xSnxTe films grown on BaF2(111) substrates using molecular beam epitaxy. The plasma treatment of the surface of the Pb1−xSnxTe films with the low and medium Sn content (x = 0–0.6) resulted in the formation of the arrays of ‘capped’ conical nanostructures with the height up to 420 nm, depending on the Sn content and treatment duration, and the surface density of ∼109 cm−2. The plasma treatment of the surface of the films with the high Sn content (x = 0.8–1) yielded the formation of a second group of flat nanostructures without ‘caps’, which had necklace-like rings consisting of multiple nanodroplets around their rims. Using transmission electron microscopy, we show that the quasi-spherical droplet ‘caps’ of the nanostructures consist of Pb ‘wrapped’ in Sn. We explain the physical mechanism of the observed plasma-assisted nanostructure self-formation in the framework of the multi-stage model including physical sputtering, redeposition, vapour-liquid-solid mechanism and micromasking mechanism.

Modification of indium sulfide (In2S3) film surface was performed by the treatment in high-density low-pressure inductively coupled argon plasma. The films with thickness of 500–800[Formula: see text]nm were fabricated on glass substrates by the thermal evaporation method and subsequent annealing in sulfur ambience. The plasma treatment of as-grown and annealed films was carried out with argon ions having the energy of 25–200[Formula: see text]eV. Nanostructuring of the film surface took place resulting in the formation of arrays of nanosized indium droplets.

We report on surface nanostructuring of Cu(In,Ga)Se2(CIGS) films using inductively coupled argon plasma treatment with the ion energy of 25–30[Formula: see text]eV within 30–120[Formula: see text]s. The films were fabricated on glass substrates using the selenization method and had a polycrystalline structure. We demonstrate that the plasma treatment results in the formation of tip-shaped nanostructure arrays with the geometrical parameters controlled by the treatment duration. The features of the surface nanostructuring using low energy ions are discussed.

AbstractConditions for ion sputtering of a PbSe/CaF_2/Si(111) epitaxial system in high-density inductively coupled plasma of high-frequency low-pressure discharge in argon have been established that ensure the formation of submicron-sized hollow lead structures on a lead-selenide surface. The surface was plasma-treated for time periods within 60–240 s at low energy (20–30 eV) of Ar^+ ions, which is close to their sputtering threshold energy. The properties of the obtained material were studied by the techniques of scanning electron microscopy and energy-dispersive X-ray microanalysis. It is shown that the characteristic size, shape, and density of surface structures can be varied within broad limits depending on the time of plasma treatment and temperature of the material surface. Physical processes responsible for the formation of hollow lead structures under the proposed conditions of plasma sputtering are considered.