Effect Of Substrate Temperature Research Articles

Effect of growth temperature on the physical properties of kesterite Cu2ZnSnS4 (CZTS) thin films

Spray pyrolysis technique was used to deposit Cu2ZnSnS4 (CZTS) thin films onto SLG substrates. The effect of substrate temperature (Tsub), ranging from 300°C to 390°C on their structure and optoelectronic properties. The structural properties reveal that all the prepared CZTS films have a kesterite structure, with a preferential orientation along (112) plane, and presence of secondary phases. XRD data indicated an improvement in crystallinity with an increase in average crystallites size, from 12.29 to 24.73 nm, while Tsub rise up to 390 °C. Raman spectra reveal CZTS formation, with two vibrational modes observed at 335 and 373 cm−1 along with a small Raman peak at 472 cm−1 associated to the Cu2S phase. Transmittance spectra show low values in the visible range with an absorption coefficient of 105 cm−2, The band gap energy (Eg) of the sprayed-CZTS films was consistently found to decrease from 1.6 to 1.38 eV as Tsub is increased from 300 to 390 °C. Hall effect measurements revealed p-type conductivity for all the samples, and the electrical conductivity increased from 1.8 to 150 (Ω.cm)−1 with substrate temperature (Tsub). Overall, experimental results demonstrate that grown CZTS thin films can be considered as a promising absorber material in solar cell devices.

Effect of Substrate Temperature on the formation of nanotwin and properties of NiCoFeCrAlTi high-entropy alloy thin films

Effect of Substrate Temperature on the formation of nanotwin and properties of NiCoFeCrAlTi high-entropy alloy thin films

Effects of substrate temperature on crystallization of Fe-based amorphous alloy prepared by selective laser melting

Selective laser melting (SLM) has potential to prepare complex shaped amorphous alloy parts, however, the almost inevitable crystallization makes it very difficult to obtain excellent performance parts. Most of previous studies focus on improving properties by optimizing parameters such as laser power, scanning speed, and scanning strategy. As is well known, the substrate is an important component in SLM devices, which directly supports and contacts the initial powder and melting pool, affecting the absorption and transfer of heat, the formation and cooling of the melting pool, and therefore exerts a significant influence on the quality and microstructure of printed parts. However, there is relatively little research on its influence. It is important and necessary to understand the influence of substrate temperature on crystallization behavior of Fe-based amorphous alloy during SLM process. Molecular dynamics (MD) simulations can provide direct evidence for the evolution of clusters and band pairs, which can help clarify the crystallization mechanism and alleviate the crystallization. In this work, the influence of substrate temperature on the crystallization and evolution of atomic clusters in Fe<sub>50</sub>Cu<sub>25</sub>Ni<sub>25</sub> amorphous alloy during SLM is investigated on an atomic scale, using MD simulation under different substrate temperatures (300–900 K), laser power values (500–800 eV/ps), and scanning speeds (0.1–1.0 nm/ps). The research results show that when the substrate temperature is lower than 750 K, the content of characteristic bond pair 1421 and the corresponding <inline-formula><tex-math id="M2">\begin{document}$ \left\langle{0,{\mathrm{ }}4,{\mathrm{ }}4,{\mathrm{ }}6}\right\rangle $\end{document}</tex-math></inline-formula> cluster increase with the substrate temperature rising, thereby increasing face-centered cubic bond pair and cluster and promoting the crystallization. When the substrate temperature rises to a value close to the glass transition temperature, the evolution of bond pairs and clusters becomes complex, which is influenced by the collaborative and competitive effects, such as the ability to form glass, melting and cooling rate. This work reveals the evolution of atomic clusters and band pairs in the SLM process of Fe-based amorphous alloys, and the initiation of crystal phases at different substrate temperatures, providing new ideas for understanding and regulating crystallization.

Effect of electron beam emission current and substrate temperature on the preparation of a CuSbS2 thin film

Effect of electron beam emission current and substrate temperature on the preparation of a CuSbS2 thin film

Achieving >28% power conversion efficiency in a-Si:H/c-Si solar cells through emitter optimization

Heterojunction solar cell efficiency is crucial for performance and commercial viability. This study investigates hydrogenated microcrystalline silicon (μc-Si:H), hydrogenated nanocrystalline silicon (nc-Si:H), and hydrogenated amorphous silicon germanium (a-SiGe:H) as p-type emitter layers in a-Si:H/c-Si heterojunction solar cells, examining their influence on short-circuit current density (Jsc), open-circuit voltage (Voc), fill factor (FF), and power conversion efficiency (PCE). Considering the reported effects of hydrogen dilution and substrate temperature on the optoelectronic properties of these materials [1, 2], we employed AMPS-1D simulations to model device performance with various emitter layers (a-Si:H(p), nc-Si:H(p), μc-Si:H(p), a-SiC:H(p), and a-SiGe:H(p)). A baseline (PCE) of 27.38% was achieved using a standard a-Si:H(p) emitter (1.8 eV bandgap). Alternative emitters yielded improved PCEs: nc-Si:H(p) (28.26% at 1.9 eV), μc-Si:H(p) (28.04% at 1.5 eV), and a-SiGe:H(p) (28.18% at 1.7 eV). These enhancements are attributed to the wider bandgaps, higher conductivity, and lower defect densities of these materials, resulting in reduced recombination losses and enhanced carrier collection. Our findings demonstrate the significant potential of emitter layer optimization for maximizing a-Si:H/c-Si heterojunction solar cell power conversion efficiency.

Effects of Substrate Temperature on Optical, Structural, and Surface Properties of Metal-Organic Vapor Phase Epitaxy-Grown MgZnO Films.

MgZnO possesses a tunable bandgap and can be prepared at relatively low temperatures, making it suitable for developing optoelectronic devices. MgxZn1-xO (x~0.1) films were grown on sapphire by metal-organic vapor phase epitaxy under different substrate-growth temperatures Ts of 350-650 °C and studied by multiple characterization technologies like X-ray diffraction (XRD), spectroscopic ellipsometry (SE), Raman scattering, extended X-ray absorption fine structure (EXAFS), and first-principle calculations. The effects of Ts on the optical, structural, and surface properties of the Mg0.1Zn0.9O films were studied penetratively. An XRD peak of nearly 35° was produced from Mg0.1Zn0.9O (0002) diffraction, while a weak peak of ~36.5° indicated MgO phase separation. SE measurements and analysis determined the energy bandgaps in the 3.29-3.91 eV range, obeying a monotonically decreasing law with increasing Ts. The theoretical bandgap of 3.347 eV, consistent with the SE-reported value, demonstrated the reliability of the SE measurement. Temperature-dependent UV-excitation Raman scattering revealed 1LO phonon splitting and temperature dependency. Zn-O and Zn-Zn atomic bonding lengths were deduced from EXAFS. It was revealed that the surface Mg amount increased with the increase in Ts. These comprehensive studies provide valuable references for Mg0.1Zn0.9O and other advanced materials.

Effect of substrate temperature on the microstructural and optical properties of chemical molecular beam deposited sb2s3 films

Effect of substrate temperature on the microstructural and optical properties of chemical molecular beam deposited sb2s3 films

Effect of Substrate Temperature on Bead Track Geometry of 316L in Directed Energy Deposition: Investigation and Regression Modeling

The optimization of process parameters in powder Directed Energy Deposition (DED) is essential for achieving consistent, high-quality bead geometries, which directly influence the performance and structural integrity of fabricated components. As a subset of additive manufacturing (AM), the DED process, also referred to as laser metal deposition (LMD), enables precise, layer-by-layer material deposition, making it highly suitable for complex geometries and part repair applications. Critical parameters, such as the laser power, feed rate, powder mass flow, and substrate temperature govern the deposition process, impacting the bead height, width, contact angle, and dilution. Inconsistent control over these variables can lead to defects, such as poor bonding, dimensional inaccuracies, and material weaknesses, ultimately compromising the final product. This paper investigates the effects of various process parameters, specifically the substrate temperature, on bead track geometry in DED processes for stainless steel (1.4404). A specialized experimental setup, integrated within a DED machine, facilitates the controlled thermal conditioning of sample sheets. Using Design of Experiments (DoE) methods, individual bead marks are generated and analyzed to assess geometric characteristics. Regression models, including both linear and quadratic approaches, are constructed to predict machine parameters for achieving the desired bead geometry at different substrate temperatures. Validation experiments confirm the accuracy and reliability of the models, particularly in predicting the bead height, bead width, and contact angle across a broad range of substrate temperatures. However, the models demonstrated limitations in accurately predicting dilution, indicating the need for further refinement. Despite some deviations in measured values, successful fabrication is achieved, demonstrating robust bonding between the bead and substrate. The developed models offer insights into optimizing DED process parameters to achieve desired bead characteristics, advancing the precision and reliability of additive manufacturing technology. Future work will focus on refining the regression models to improve predictions, particularly for dilution, and further investigate non-linear interactions between process variables.

Plasma emission spectroscopy for studying Bi2S3 produced by pulsed laser deposition and effects of substrate temperature on structural, morphological, and optical properties of thin films

This research underscores the role of plasma analysis in enhancing the reproducibility of Bi2S3 thin films synthesized via pulsed laser deposition (PLD). Through optical emission spectroscopy (OES), we analyzed the dynamics of the Bi2S3 plasma, focusing on the transitions of neutral and singly ionized sulfur and bismuth atoms. Thin films were grown at varying substrate temperatures (WST, 100 °C, 150 °C, 200 °C, and 250 °C), and structural and morphological characterizations confirmed a polycrystalline nature, with particle size increasing at higher deposition temperatures. The films exhibited transmittance values ranging from 8 % to 26 % and a bandgap from 1.61 to 1.75 eV as the substrate temperature increased. Bi2S3 films also demonstrated n-type conductivity at temperatures above room temperature. These findings highlight the influence of substrate temperature on the structural and optoelectronic properties of Bi2S3 films, with optimal characteristics for optoelectronic applications consistently achieved at deposition temperatures between 150 °C and 200 °C.

Photocatalytic performance and solar cell simulations of TiO2–SnO2:F mixed oxide thin films grown by spray pyrolysis method

Mixed oxide titanium dioxide (TiO2) and fluorine doped tin oxide (SnO2:F) thin films have been grown, using spray pyrolysis technique, at various substrate temperatures (Ts) ranging from 250 to 400 °C with a step of 50 °C. Samples were examined using X-ray diffraction (XRD), optical microscopy, spectrophotometry and spectrofluorimetry, with special emphasis on the evolution of their physico-chemical properties versus substrate temperature. In fact, X-ray diffraction analysis showed that a substrate temperature of about 350 °C exhibits the presence of both anatase phase of TiO2 and tetragonal structure of SnO2:F compounds. A direct band gap of about 3.91 eV was obtained. Envelope method, based on transmission spectrum, was investigated in order to estimate the film thickness and some optical parameters such as real and imaginary parts of dielectric constant. Wemple Di-Dominico and Spizer Fan models were applied in order to determine the effect of substrate temperature on some dispersion parameters. Photoluminescence spectra showed different emissions in the visible region. The photodegradation mechanism of both Rhodamine B (RhB) and Malachite Green (MG) pollutants using TiO2–SnO2:F coupled oxide layer, grown at 350 °C, was discussed and an efficiency of about 90 %, after 3 h of sun irradiation, was achieved. Additionally, the layer exhibits good stability, recoverability and reusability after a cyclic test of 9 h, making it suitable for industrial applications. As a secondary application, a numerical simulation of TiO2–SnO2:F/CdS/CIGS solar cell, using SCAPS-1D software, was investigated for the first time. An open circuit voltage of about 613 mV was obtained, the current density Jsc was in the order of 33.49 mA/cm2, the Fill Factor FF and the efficiency were in the order of 79.13, 16.23 %, respectively.

On the Effects of Substrate Temperature on Glass Internal Modification Using Femtosecond Laser Pulses

Abstract The effects of substrate temperature on laser focal position and tear-drop morphology in laser internal modification of glass are investigated. A model is derived to predict the shift of the tear-drop at high substrate temperature. Femtosecond laser pulses are scanned inside borosilicate glass at room temperature, 150 °C, and 200 °C using a pulse energy of 4.5–18 µJ, a scanning speed of 5–20 mm/s, and a distance between lens and glass of 9.56–10.76 mm. Temperature effects are characterized by defining a height (width) gain ratio as the ratio between the tear-drop height (width) measured at high temperature to that measured at room temperature. Thermal expansion is simulated using a profile temperature acquired by a thermal camera and image processing. Results show that substrate temperature has a significant effect on self-focusing, and modifications at 200 °C show a relaxed discoloration compared to 150 °C and room temperature. Analytical predictions match the measurements of focal position in the distance of 9.56–9.96 mm at 200 °C where self-focusing is not significant while underestimating the measurements for the distance of 10.76 mm and 10.36 mm by 30–50 µm. At 200 °C, the tear-drop's gain ratio is increased when the pulse energy is increased in the range of 4.5–18 µJ. Within this pulse energy range and at 200 °C, the maximum width gain is 10–100% higher compared to the maximum height gain.

Synthesis and Structural Modulation of Nanoporous Copper Films by Magnetron Sputtering and One-Step Dealloying.

Nanoporous copper (np-Cu) has attracted much more attention due to its lower cost compared to other noble metals and high functionality in practical use. Herein, Al100-xCux(x = 13-88 at.%) precursor films with thicknesses of 0.16-1.1 μm were fabricated by varying magnetron co-sputtering parameters. Subsequently, utilizing a one-step dealloying strategy, a series of np-Cu films with ligament sizes ranging from 11.4-19.0 nm were synthesized. The effects of precursor composition and substrate temperature on the microstructure of np-Cu films were investigated. As the atomic ratio of Cu increases from 15 to 34, the np-Cu film detached from the substrate gradually transforms into a bi-continuous ligament-channel structure that is well bonded to the substrate. Furthermore, the novel bi-layer hierarchical np-Cu films were successfully prepared based on single-layer nanoporous films. Our findings not only contribute to the systematic understanding of the modification of the morphology and structure of np-Cu films but also offer a valuable framework for the design and fabrication of other non-noble nanoporous metals with tailored properties.

Effect of substrate temperature on the performance of Sb2Se3 thin film solar cells fabricated by chemical-molecular beam deposition method

Antimony triselenide (Sb2Se3) stands as a promising candidate for photovoltaic (PV) applications due to its favorable material- and optoelectronic properties. However, the realization of further advancements in device efficiency is hindered by the substantial deficit in open-circuit voltage (VOC) attributed to the presence of multiple defect states and detrimental recombination losses.In this work, solar cells based on Sb2Se3 absorber layers deposited by chemical-molecular beam deposition method at substrate temperatures of 400 °C, 450 °C, and 500 °C. Due to the precise control of the Sb/Se ratio, Sb2Se3 thin films with stoichiometric composition were obtained, which was confirmed by energy-dispersive X-ray spectroscopy. The effect of substrate temperature on the morphology and electrical properties of Sb2Se3 thin-films were characterized by scanning electron microscopy and hot probe method. The PV performance of Mo/Sb2Se3/ZnCdS/CdS/ZnO/ITO/Au devices were investigated by current-voltage characteristics, and external quantum efficiency. The conductivity values tend to increase from 1.2 × 10–6 to 4.6 × 10–4 (Ω cm)-1 as the substrate temperature increased. Whereas, the trap-state density was determined between 7.3 × 1013 – 1.7 × 1014 cm-3 in the absorber layer by the space charge limited current method. Ultimatety, it has been shown that defect densities in Sb2Se3 films can be suppressed to some extent by optimizing the substrate temperature. Best solar cell performance of 5.36%, resulting from VOC of 476 mV, short-circuit current densit of 22.97 mA/cm−2, and fill factor of 49% at the substrate temperature of 450 °C.

Effect of substrate temperature on the physical and sensing properties of nanostructured Fe2O3 thin films

Using Chemical Bath Deposition (CBD) Method and various substrate temperatures, Fe2O3 films were successfully deposited. The produced film thickness was around (320 nm). Using X-ray diffraction, researchers may examine the polycrystalline structure of Fe2O3 thin films. These nanofilms contain strong peaks at 2θ =32.21, suggesting a preferred orientation along the (110) plane, and the grain size increases with substrate temperature, according to XRD tests. When the base temperature was raised from 350 to 450 o C, the strain parameter decreased from 31.35 to 28.43. AFM testing of the surface morphology of the deposition of material yields excellent homogenous coatings. The findings show that the average particle size of the nanoparticles ranges from (69.8 to 32.7) nm. SEM images show Fe2O3 films at (350, 400, 450) °C. Increased temperature reduces grain size, influencing morphology variations. The absorbance increases with substrate temperatures and decreases rapidly at short wavelengths, which correspond to the energy gap. The transmittance increases with increasing wavelength range. It decreases with rising substrate temperatures. The band gap values vary from 2.17 eV to 2.06 eV by increasing the substrate temperatures from 350 to 450 o C. It was discovered that the band gap reduces as the temperature of the Fe2O3 substrate increases. In addition, the optical constants for all films, including the absorption coefficient, the refractive index, and the extinction coefficient, were computed. Fe2O3 film's resistance over time at 350, 400, and 450°C for 300 ppm NO2 demonstrates oxidation effect and temperature sensitivity. Sensitivity decreases with higher base temperature due to charge carrier recombination, affecting NO2 response.

Conventional epitaxy of NiO thin films on muscovite mica and c-Al2O3 substrates

Fiber-textured and epitaxial NiO thin films were deposited on Si(100), c-Al2O3, and muscovite mica(001) substrates using reactive magnetron sputtering at substrate temperatures of 300 °C and 400 °C, to investigate the effect of film thickness and substrate temperature on epitaxial growth of NiO films. The as-deposited films exhibited a face-centered cubic structure with a larger lattice constant, attributed to strain induced during the sputtering process. With an increase in substrate temperature to 400 °C, the d-spacing decreased due to strain release, approaching the NiO bulk value for the thickest film. The NiO film grown on Si(100) displayed fiber texture. On c-plane sapphire, NiO thin films exhibited twin domains and three-fold symmetry, consistent with expected crystallographic orientation relationship for NaCl-structured materials on sapphire:(111)NiO∥(0001)Al2O3and[01¯1]NiO∥[1¯010]Al2O3, [011¯]NiO∥[101¯0]Al2O3. On muscovite mica(001) substrates, the observed epitaxial shows that the mechanism is conventional epitaxy, rather than van der Waals epitaxy, consistent with the epitaxial growth of the non-layered non-van-der-Waals compound NiO. The epitaxial relationship was identified as of (111)NiO∥(001)Mica and [01¯1]NiO∥[010]Mica, [011¯]NiO∥[01¯0]Mica.

Influence of substrate temperature and Mn/Y co-doping concentration on the morphological, structural and optical properties of CuO nanostructured film deposited by the spray pyrolysis method

In this work, the effect of substrate temperature (ST) during deposition and dopant amount of Mn (1,3,5, and 7 %) and Y(3 %), (Mn/Y), on the physical properties of copper oxide (CuO) the nanostructured film were analyzed using different diagnostic tools. The pure and (Mn, Y) co-doped CuO thin films were deposited by the spray pyrolysis method, which is effective and easy to apply for any substrate. Deposited pure and (Mn,Y) co-doped CuO nanostructured films were investigated by X-ray diffraction (XRD), UV–Vis spectroscopy, and Field emission scanning electron microscopy (FESEM) techniques to analyze the influence of ST and co-doping on the structural, morphological, and optical properties of prepared films. The FESEM is used to visualize nanostructures on the surface of the film. Also, it is observed that the surface morphology of CuO film changes from a spherical-like to a nanocloumnar-like structure with increasing substrate temperature. The XRD diffractograms confirm the monoclinic crystal structure of CuO, in polycrystalline nature for all deposited films. UV–Vis spectra suggest changing the optical absorbance and the band gap of the pure and Mn/Y co-doped CuO nanostructured films. In the first investigation of this study, the better substrate temperature was obtained as 400 °C according to results. In the second part, the effect of Y and Mn doping with different content was analyzed for the CuO film deposited at the chosen ST of 400 °C. There is no observable crystalline structure variation in the XRD pattern, but the size of nanostructure and dislocation density are varied with Mn/Y co-doping. FESEM micrographs confirm the impact of the co-doping concentration on the size, shape, and surface properties of CuO nanostructured film. In addition, the optical band gap increases with Mn doping up to 3 % of Mn content and it was determined as 2.69 eV for the sample 3Mn/Y@CuO nanostructured film. The obtained results suggest that the substrate temperature has an important impact on the physical properties of the spray deposited CuO nanostructured film, and the structural, optical, and surface properties of the CuO nanostructured films may be engineered by Mn/Y doping concentration.

Influence of substrate temperature on plasma-enhanced chemical vapor deposition to improve the surface flashover performance of epoxy resin

Abstract Epoxy resin composites are widely used as insulating and supporting materials in high-voltage power systems due to their excellent mechanical and electrical properties. However, long-term operation under high-voltage direct current induces surface flashover. Plasma enhanced chemical vapor deposition (PECVD) has been shown to effectively improve the surface insulation properties of epoxy resin. However, the influence of substrate temperature on the film composition, stress, morphology, and surface flashover performance remains unclear. This study uses PECVD to treat epoxy resin, enhancing its surface flashover performance. Tetraethoxysilane is used as the precursor to deposit nano-scale SiO x films on the epoxy resin surface. The effects of different substrate temperatures on the surface flashover voltage, physicochemical properties, and mechanical properties of epoxy resin are characterized. The results show that the surface flashover voltage increases and then saturates with increasing substrate temperature, improving by 27.4% at 60 °C compared to untreated samples. The surface roughness of epoxy resin decreases after plasma deposition, while highly oxidized silicon-containing functional groups are introduced. When the substrate temperature increases from 20 °C to 60 °C, the interfacial bonding strength improves by 25.9%. This study provides a simple, efficient, and controllable method to enhance the surface flashover performance of epoxy resin, promoting the application of this technology in engineering practice.

The Impact of Substrate Temperature on the Adhesion Strength of Electroplated Copper on an Al-Doped ZnO/Si System.

This research, which involved a comprehensive methodology, including depositing electroplated copper on a copper seed layer and Al-doped ZnO (AZO) thin films on textured silicon substrates using DC magnetron sputtering with varying substrate heating, has yielded significant findings. The study thoroughly investigated the effects of substrate temperature (Ts) on copper adhesion strength and morphology using the peel force test and electron microscopy. The peel force test was conducted at angles of 90°, 135°, and 180°. The average adhesion strength was about 0.2 N/mm for the samples without substrate heating. For the samples with substrate heating at 100 °C, the average peeling force of the electroplated copper film was about 1 N/mm. The average peeling force increased to 1.5 N/mm as the substrate heating temperature increased to 200 °C. The surface roughness increases as the annealing temperature of the Cu/AZO/Si sample increases. These findings not only provide a reliable and robust method for applying AZO transparent conductive films onto silicon solar cells but also underscore its potential to significantly enhance the efficiency and durability of solar cells significantly, thereby instilling confidence in the field of solar cell technology.

Effect of substrate temperature on In2S3 thin films using nebulizer spray pyrolysis method for photodetector applications

In this work, Indium Sulfide (In2S3) thin films were prepared using an economical nebulizer spray pyrolysis technique by various substrate temperatures from 250 °C to 375 °C in steps of 25 °C to evaluate their photo sensing properties. X-ray diffraction (XRD) patterns confirm the presence of In2S3 with face centered cubic structure for all substrate temperatures. The densely packed small spherical grain-sized particles were observed for In2S3 films deposited at 350 °C using Field emission scanning electron microscope (FESEM) analysis. The optical bandgap values were decreased from 3.16 eV to 2.28 eV, with increment in coating temperatures from 250 °C to 350 °C. The high intensity Photoluminescence (PL) peak is observed at 480 nm for the film coated at 350 °C is due to higher rate of electron–hole pair recombination. The photo sensing analysis revealed that the In2S3 thin films deposited at 350 °C, has the maximum responsivity (R) of 9.09 × 10−2 A W−1, detectivity (D*) of 8.25 × 1010 Jones, and external quantum efficiency (EQE) of 21.2%. Increasing the substrate temperature results in a significant enhancement of photo sensing characteristics.

Influence of physicochemical factors on the specific activity of proteases used in cheesemaking biotechnology

The formation of a clot under the influence of proteolytic enzymes is an essential stage in cheesemaking technology. Depending on their composition, milk-clotting enzyme preparations have a different effect on the quality characteristics of the clot, whey separation, and yield of the finished product. At present, the Russian market offers a wide range of domestic and imported milk-clotting enzyme preparations. In this connection, the choice of a milk coagulant by cheese makers should be carried out in accordance with the cheese group produced by the enterprise. The milk-clotting activity of enzyme preparations depends not only on the active acidity of the mixture, but also on the temperature of the solution used to obtain them. It is the solution temperature that has a determining effect on the duration of the coagulation process and, therefore, the quality of the formed clot. Research into the specific activity of milk-clotting enzyme preparations, obtained in a working solution with different active acidity (pH from 4.0 to 8.0), showed their milk-clotting activity to decrease significantly upon pH shifting to the alkaline region. Application of solutions with a pH of 4.0 led to an increase in the milk-clotting activity of bovine pepsin, VNIIMS SG-50 rennet-bovine preparation, and rennet enzyme by 94, 72, and 36%, respectively, relative to the control. Bovine pepsin demonstrated the highest sensitivity to fluctuations in active acidity. A study into the effect of substrate temperature in the range from 30 to 40 °C established rennet to be the most sensitive preparation to temperature changes. It is concluded that a properly selected enzyme composition is an effective means for affecting the quality of cheese products.