Chemical Deposition Research Articles

Van der Waals Epitaxy of High-Quality Transition Metal Dichalcogenides on Single-Crystal Hexagonal Boron Nitride.

Van der Waals (vdW) heterostructures comprising of transition metal dichalcogenides (TMDs) and hexagonal boron nitride (h-BN) are promising building blocks for novel 2D devices. The vdW epitaxy provides a straightforward integration method for fabricating high-quality TMDs/h-BN vertical heterostructures. In this work, the vdW epitaxy of high-quality single-crystal HfSe2 on epitaxial h-BN/sapphire substrates by chemical vapor deposition is demonstrated. The epitaxial HfSe2 layers exhibit a uniform and atomically sharp interface with the underlying h-BN template, and the epitaxial relationship between HfSe2 and h-BN/sapphire is determined to HfSe2 (0001)[1 10]//h-BN (0001)[1 00]//sapphire (0001)[1 00]. Impressively, the full width at half maximum of the rocking curve for the epitaxial HfSe2 layer on single-crystal h-BN is as narrow as 9.6 arcmin, indicating an extremely high degree of out-plane orientation and high crystallinity. Benefitting from the high crystalline quality of HfSe2 epilayers and the weak interfacial scattering of HfSe2/h-BN, the photodetector fabricated from the vdW epitaxial HfSe2 on single-crystal h-BN shows the best performance with an on/off ratio of 1×104 and a responsivity up to 43mAW-1. Furthermore, the vdW epitaxy of other TMDs such as HfS2, ZrS2, and ZrSe2 is also experimentally demonstrated on single-crystal h-BN, suggesting the broad applicability of the h-BN template for the vdW epitaxy.

Local Strain-Dependent Etching Patterns of Chemical Vapor Deposited Molybdenum Disulfide.

This study reveals a local strain-dependent etching behavior that enables the formation of distinguished etching patterns in differently strained chemical vapor deposited (CVD) 2D molybdenum disulfide (MoS2) monolayers. It is demonstrated that when the local tensile strain of CVD 2D MoS2 is as uniformly low as ɛ ≈ 0.33% or less, the oxidative etching pattern possesses conventional triangular etching pits (TEPs), while when the local tensile strain is as uniformly high as ɛ ≈ 0.55% or larger, the oxidative etching pattern consist of uniformly oriented hexagonal etching channels (HECs). More interestingly, when the CVD 2D MoS2 monolayer has heterogenous strain distribution from ɛ ≈ 0.55% (center region) to ɛ ≈ 0.33% (perimeter region), the oxidative etching pattern comprise of non-uniformly hexagonal-mixed-parallel etching channels (HPECs). The further characterization and analysis reveal the formation mechanism of such strain-dependent etching patterns is built on the local strain-related fractures propagation under oxidative etching, as well as the anisotropy fractures-based oxidative etching kinetics. This study may enhance the understanding of the relationship between etching and growth features of 2D TMDs, and paves the way to etching-nanostructured (or defect) engineering of 2D TMDs and other 2D materials for potential applications in electrocatalysis and optoelectronics.

Load‐Bearing Structure Inspired Cellulose‐Based Aerogel With High Resilience and Water Tolerance

AbstractCellulose‐based aerogels possess satisfactory sustainability, porosity, and resilience, which are promising materials to replace traditional petroleum‐based foams. However, the viscous aggregation formed between hydrophilic fibers and the pore collapse caused by weak support force pose challenges for their further applications. Here, a load‐bearing structure‐inspired cellulose‐based aerogel is innovatively developed with excellent elasticity and water tolerance through surface‐interface modulation. Specifically, cellulose and polyvinyl alcohol (PVA) form interwoven skeletons by non‐directional freeze drying. Crucially, the rhamnolipid surfactant assists in forming stable and uniform bubbles, and drives the regularization of frame structure during the freezing process, promoting the construction of refined mechanical structures. Besides, the interfacial enhancement by esterification reaction of citric acid and the encapsulation by hydrophobic silane via chemical vapor deposition endow aerogels with better resilience and water tolerance. The as‐prepared aerogels can withstand intensive compression cycle tests and possess the ability to rebound over 10 times underwater. Even after 12 h wet treatment, the strain and stress loss respectively decrease by ≈55.5% and ≈14% compare with the initial unregulated aerogels after 500 cycles of 80% compression. Surprisingly, they have excellent cushioning performance beyond expanded polystyrene (EPS) and expanded polyethylene (EPE) in simulated road transportation packaging applications, indicating their potential in new‐generation cushioning materials.

Layer Number and Stacking Engineering of MoS2 Crystals for High-Performance Polarization-Sensitive Photodetector.

The layer and stacking engineering of two-dimensional (2D) transition-metal dichalcogenides (TMDs) gives rise to novel phenomena and multiapplications; thus, TMDs have garnered considerable attention. However, the precisely customized fabrication of stacked 2D materials to date is largely limited to the lack of effective and controllable growth strategies, prone to the unpredictable stacking orders and randomly distributed nucleation sites. Here, we devise an optimized chemical vapor deposition approach for modulating the MoS2 single crystals from monolayer to multilayer with diverse stacking configurations. Significantly, the phototransistor based on monolayer MoS2 single crystal exhibits an ultrasensitive performance with a high photoresponsivity (R) of 3.3 × 104 A W-1 and a remarkable detectivity (D*) of above 1.7 × 1014 Jones at 405 nm light illumination. Ultralow-frequency and angle-resolved polarized Raman spectroscopy is used to systematically uncover the delicate interlayer interactions and crystallographic anisotropy. Moreover, the polarization-sensitive photodetectors using 1-3L MoS2 show a layer number-dependent anisotropic performance, with dichroism ratios of 1.36, 1.44, and 1.52. This work offers a promising method to not only enable the fabrication of new customized layer-, stacking-, and twist-2D materials but also provides the foundation for the development of advanced polarization-sensitive and optoelectronic devices based on stacking transitions.

Microstructured Reflective Coatings on Commodity Textiles for Passive Personal Cooling.

As the effects of climate change become more severe and widespread, maintaining personal thermal homeostasis becomes necessary for survival. In principle, advanced textiles and garments have the ability to leverage light absorption, transmission and/or reflection, in addition to straightforward convection, to heat or cool bodies in extreme temperature conditions. For cooling, in particular, surfaces adept at selectively reflecting or refracting high-energy incident light (200 nm-2.5 mm) from the sun while transmitting or emitting infrared light (8-13 mm) from radiant body heat boast the ability to maintain cooler body temperatures, even when exposed to direct sunlight and the open sky. Here, we present a strategy to transform common clothing into implements for passive personal cooling. As confirmed by Mie scattering calculations, cheap and biocompatible calcium carbonate and barium sulfate micro/nanoparticles are found to serve as suitable reflectors for radiative cooling. Finite-difference time domain simulations reveal, surprisingly, that higher reflectance is achieved with surface coatings containing these materials, as compared to extruded metamaterial fibers containing CaCO3 and BaSO4 particles embedded within a polymer matrix. A stepwise process involving photoinitiated chemical vapor deposition and ion-exchange driven crystal growth is used to create a lamellar composite coating comprised of alternating CaCO3 and BaSO4 nano/microparticle layers directly on the surface of common fabrics. A polyester poplin fabric coated in this manner shows a cooling ability of up to 8 °C compared to an uncoated sample, achieving a maximum cooling of 6 °C below ambient temperature. Wash and durability testing of the lamellar coating reveal no mechanical degradation and no evident attenuation in the material's performance, affirming its resilience and long-term effectiveness as a functional textile coating for personal cooling. We also assess the performance of our coated fabrics in multiple outdoor environments to conclude that we can achieve up to 3.4 °C of sub-ambient cooling in optically complex built environments.

A Novel Mechanism Based on Oxygen Vacancies to Describe Isobutylene and Ammonia Sensing of p-Type Cr2O3 and Ti-Doped Cr2O3 Thin Films

Gas sensors based on metal oxide semiconductors (MOS) have been widely used for the detection and monitoring of flammable and toxic gases. In this paper, p-type Cr2O3 and Ti-doped Cr2O3 (CTO) thin films were synthesized using an aerosol-assisted chemical vapor deposition (AACVD) method. Detailed analysis of the thin films deposited, including structural information, their elemental composition, oxidation state, and morphology, was investigated using XRD, Raman analysis, SEM, and XPS. All the gas sensors based on pristine Cr2O3 and CTO exhibited a reversible response and good sensitivity to isobutylene (C4H8) and ammonia (NH3) gases. Doping Ti into the Cr2O3 lattice improves the response of the CTO-based sensors to C4H8 and NH3. We describe a novel mechanism for the gas sensitivity of p-type metal oxides based on variations in the oxygen vacancy concentration.

Two-Dimensional MoSi2N4 Family: Progress and Perspectives Form Theory.

Recently, a new two-dimensional (2D) layered MoSi2N4 has been successfully synthesized by chemical vapor deposition without knowing the 3D counterparts [ Science 2020, 369, 670-674]. The unique septuple-atomic-layer structure and diverse composition of MoSi2N4 have drawn tremendous interest in studying 2D MA2Z4 systems based on the MoSi2N4 structure. As an emerging family of 2D materials, MA2Z4 materials exhibit a wide range of properties and excellent tunability, making them highly promising for various applications. Herein, we summarize recent significant progress in property characterization of the MA2Z4 family. The electronic, magnetic, thermal transport, and superconducting properties, including their tunability through strain engineering and elemental substitution, are presented and elaborated in detail. Further perspectives and new opportunities of the emerging MA2Z4 family are presented at the end of this Perspective.

Composition analysis of β-(In x Ga1-x )2O3 thin films coherently grown on (010) β-Ga2O3 via mist CVD

ABSTRACT This study investigates the compositional analysis and growth of β-(In x Ga1-x )2O3 thin films on (010) β-Ga2O3 substrates using mist chemical vapor deposition (CVD), including the effects of the growth temperature. We investigated the correlation between In composition and b-axis length in coherently grown films, vital for developing high-electron-mobility transistors and other devices based on β-(In x Ga1-x )2O3. Analytical techniques, including X-ray diffraction (XRD), reciprocal space mapping, and atomic force microscopy, were employed to evaluate crystal structure, strain relaxation, and surface morphology. The study identified a linear relationship between In composition and b-axis length in coherently grown films, facilitating accurate composition determination from XRD peak positions. The films demonstrated high surface flatness with root-mean-square roughness below 0.6 nm, though minor relaxation and granular features emerged at higher In compositions (x = 0.083) at the growth temperature of 750°C. XRD results revealed that lattice relaxation were observed at a growth temperature of 700°C despite low In composition. In contrast, at 800°C, the In composition was higher than at 750°C, and coherent growth was achieved. The surface morphology was the flattest at 750°C. These findings indicate that the growth temperature plays a crucial role in the mist CVD growth of β-(In x Ga1-x )2O3 thin films. This study offers insights into the relationship between In composition and lattice parameters in coherently grown β-(In x Ga1-x )2O3 films, as well as the effect of growth conditions, contributing to the advancement of ultra-wide bandgap semiconductor device development.

Accelerating Optimal Synthesis of Atomically Thin MoS2: A Constrained Bayesian Optimization Guided Brachistochrone Approach

AbstractA machine learning (ML) guided approach is presented for the accelerated optimization of chemical vapor deposition (CVD) synthesis of 2D materials toward the highest quality, starting from low‐quality or unsuccessful synthesis conditions. Using 26 sets of these synthesis conditions as the initial training dataset, our method systematically guides experimental synthesis towards optoelectronic‐grade monolayer MoS2 flakes. A‐exciton linewidth (σA) as narrow as 38 meV could be achieved in 2D MoS2 flakes after only an additional 35 trials (reflecting 15% of the full factorial design dataset for training purposes). In practical terms, this reflects a decrease of the possible experimental time to optimize the parameters from up to one year to about two months. This remarkable efficiency was achieved by formulating a constrained sequencing optimization problem solved via a combination of constraint learning and Bayesian Optimization with the narrowness of σA as the single target metric. By employing graph‐based semi‐supervised learning with data acquired through a multi‐criteria sampling method, the constraint model effectively delineates and refines the feasible design space for monolayer flake production. Additionally, the Gaussian Process regression effectively captures the relationships between synthesis parameters and outcomes, offering high predictive capability along with a measure of prediction uncertainty. This method is scalable to a higher number of synthesis parameters and target metrics and is transferrable to other materials and types of reactors. This study envisions that this method will be fundamental for CVD and similar techniques in the future.

Fractal analyses of AlxGa1−xN thin film surfaces on AlN at different annealing temperatures

The determination of heteromorphological structures formed on the surface during annealing of AlxGa1−xN thin film grown on sapphire substrate using the metal organic chemical vapor deposition technique at different temperatures was investigated by fractal analysis method. The images of the surfaces of the thin films were taken by atomic force microscopy (AFM) at temperatures of 900, 1000, 1050 and 1200 °C respectively. AFM images were digitised in bitmap format according to the annealing temperatures. It was determined that the fractal dimensions obtained a linear correlation with the annealing temperatures. The results confirm the hypothesis that surface relaxation by the thermal action can produce fractal-like structures at particle or cluster boundaries. It is found that the observed cluster formation of superficial particles decreases as increasing temperature. The increase in temperature reduces the rate of superficial particle coating. To determine the surface roughness of the AlxGa1−xN thin film according to the annealing temperature, the AFM images were digitized in tagged image file format and the statistical root mean square, mean value, mean roughness, skewness and kurtosis values of the films were calculated. The roughness is a result of the thin film surface heteromorphology formed due to the specific annealing process. It is proved that the fractal dimensions of the AlxGa1−xN thin film increase as the annealing temperature rises. The particles coalesce on the surface and cluster in different types and sizes at each different annealing temperature, forming islets of different sizes. The skewness and kurtosis values show a different and irregular change.

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 (HVDC) 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 (TEOS) is used as the precursor to deposit nano-scale SiOx 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.

Electrical Transport Properties of PbS Quantum Dot/Graphene Heterostructures.

The integration of PbS quantum dots (QDs) with graphene represents a notable advancement in enhancing the optoelectronic properties of quantum-dot-based devices. This study investigated the electrical transport properties of PbS quantum dot (QD)/graphene heterostructures, leveraging the high carrier mobility of graphene. We fabricated QD/graphene/SiO2/Si heterostructures by synthesizing p-type monolayer graphene via chemical vapor deposition and spin-coating PbS QDs on the surface. Then, we used a low-temperature electrical transport measurement system to study the electrical transport properties of the heterostructure under different temperature, gate voltage, and light conditions and compared them with bare graphene samples. The results indicated that the QD/graphene samples exhibited higher resistance than graphene alone, with both resistances slightly increasing with temperature. The QD/graphene samples exhibited significant hole doping, with conductivity increasing from 0.0002 Ω-1 to 0.0007 Ω-1 under gate voltage modulation. As the temperature increased from 5 K to 300 K, hole mobility decreased from 1200 cm2V-1s-1 to 400 cm2V-1s-1 and electron mobility decreased from 800 cm2V-1s-1 to 200 cm2V-1s-1. Infrared illumination reduced resistance, thereby enhancing conductivity, with a resistance change of about 0.4%/mW at a gate voltage of 125 V, demonstrating the potential of these heterostructures for infrared photodetector applications. These findings offer significant insights into the charge transport mechanisms in low-dimensional materials, paving the way for high-performance optoelectronic devices.

Heteroepitaxial Growth of NiO Thin Films on (‐201) β‐Ga2O3 by Mist Chemical Vapor Deposition

The growth of NiO epitaxial thin films on (‐201) β‐Ga2O3 by mist chemical vapor deposition (CVD) and the effects of carrier gas selection (N2 and O2) and substrate preannealing treatment on the structural and morphological properties on the grown thin films are explored. X‐ray diffraction analysis reveals successful epitaxial growth with the orientation relationship (111) NiO [0‐11] || (‐201) β‐Ga2O3 [010]. As a carrier gas, O2 results in single‐domain NiO films while N2 leads to the formation of rotational domains. Atomic force microscopy and field‐emission scanning electron microscopy confirm the lateral growth of NiO films, thus highlighting the importance of substrate preannealing at 1200 °C in oxygen atmosphere to obtain flat, high‐quality films. The results demonstrate that the method of mist CVD combined with appropriate substrate preparation and carrier gas selection is effective for the growth of high‐quality NiO/β‐Ga2O3 heterostructures. This achievement opens new possibilities for the development of wide‐bandgap p–n heterojunctions, potentially advancing the field of high‐power oxide‐based electronic devices.

Impact of water vapor on the 2D MoS2 growth in metal-organic chemical vapor deposition

In the presented work, the method of metal–organic chemical vapor deposition (MOCVD) using Mo(CO)6 and H2S assisted by oxidative etching with water vapor, was employed for the synthesis of MoS2. This study was aimed at detailed investigation of the films' properties obtained via this method and identifying methods for elimination of such disadvantages as the carbon impurities and the small size of crystalline domains in the films. It was found that in the temperature range from 850 °C to 950 °C, the effect of water vapor on the morphology of MoS2 is significantly different. The study of the chemical states of molybdenum and sulfur made it possible to associate the size of the crystal domains formed with the efficiency of removing the oxidized states of Mo6+ and S6+. It is assumed that the increase in the domains’ size is due to rapid lateral growth, resulting from the complete removal of the oxidized states at the edges, as well as a decrease in the density of nucleation centers due to the etching of less stable seeds on the substrate surface.

Adjusting the Covalency of Metal-Oxygen Bonds in CuBi2O4 by Zn Cation Doping to Achieve Highly Efficient Photocathodes.

Zn doped CuBi2O4 photocathodes are prepared by using a low-cost solution-based spray pyrolysis method. The doping of Zn in CuBi2O4 promotes the separation and migration of carriers and effectively increases the carrier density. Compared with CuBi2O4 alone, the photoelectrochemical activity of the Zn doped CuBi2O4 photoelectrode is improved with the photocurrent density of -0.56 mA/cm2 at 0.4 V vs. RHE. This improvement is due to the lower electronegativity of Zn, which leads to the covalent increase of Cu-O and Bi-O bonds in CuBi2O4, which limits the recombination of photogenerated electrons and holes and improves charge separation and transport. This study presents an innovative approach to enhance the charge separation efficiencies of photocathodes by implementing element doping strategies, which may contribute to further research on photocatalytic water splitting.

Large-Size and Ultrahigh Purity Tungsten with Enhanced Physical Properties via Chemical Vapor Deposition.

Conventional powder metallurgy techniques fail to meet the demands for ultrahigh purity tungsten (UHPW) and scalable component sizes required by the semiconductor industry. In this study, ultrahigh purity (99.999998 wt %) large-size tungsten parts, with an adjustable thickness and a diameter of 350 mm, were prepared via a chemical vapor deposition (CVD) method using ultrahigh purity (99.9999 wt %) tungsten hexafluoride (WF6) as the precursor. The microstructure and physical properties of the resulting CVD-UHPW were evaluated and compared with those of powder metallurgy tungsten (PM-W). The results indicate that CVD-UHPW displays a columnar grain microstructure with a lower dislocation density and internal strain, whereas PM-W shows an equiaxed grain microstructure. CVD-UHPW has a density of 19.17 g/cm3, closely matching the theoretical density of tungsten (19.35 g/cm3) and significantly higher than PM-W's density of 18.79 g/cm3. The specific heat capacities of CVD-UHPW, measured from 298 to 1473 K, range from 0.113 to 0.146 J/g·K, similar to PM-W's range of 0.120 to 0.151 J/g·K. CVD-UHPW shows improved electrical and thermal conductivities compared to PM-W, with values ranging from 1.68 × 106 to 1.78 × 107 S/m and 105.7 to 196.4 W/(m·K) from 298 to 1473 K. This study highlights the potential of the CVD method for the large-scale production of ultrahigh purity tungsten parts, emphasizing its significant applicability across various industries.

Direct Growth of Bio-Graphene Using Modified-Chemical Vapor Deposition For Straight-Forward Characterization

Oil Palm Shell (OPS) is subjected to heating, resulting in gaseous compound release. These compounds are deposited on the substrate to produce Bio-Graphene. Through Chemical Vapor Deposition (CVD), the process is optimized by growing environment parameters during the production process. This process involves the controlled deposition of gaseous compounds onto a substrate under two different positions of the alumina boat (ABC-1 and ABC-2). Direct deposition on silicon wafers eliminated etching and transfer sequences, simplifying Bio-Graphene characterization. Field Emission Scanning Electron Microscope, Atomic Force Microscope, Raman Spectroscopy, X-ray diffraction, and I-V measurement were employed to characterize the Bio-Graphene. The findings revealed that the better-closed settings (ABC-2) facilitated the growth of high-quality Bio-Graphene with better crystallinity, detectable growth spurt, estimated few-layer thickness, larger growth area, and lower surface roughness. Optimizing the deposition environment at ABC-2 significantly enhances the quality and crystallinity of Bio-Graphene from OPS, paving the way for future applications.

Bayesian Optimization for Controlled Chemical Vapor Deposition Growth of WS2.

We applied Bayesian optimization (BO), a machine learning (ML) technique, to optimize the growth conditions of monolayer WS2 using photoluminescence (PL) intensity as the objective function. Through iterative experiments guided by BO, an improvement of 86.6% in PL intensity is achieved within 13 optimization rounds. Statistical analysis revealed the relationships between growth conditions and PL intensity, highlighting the importance of critical conditions, including the tungsten source concentration and Ar flow rate. Furthermore, the effectiveness of BO is demonstrated by comparison with random search, showing its ability to converge to optimal conditions with fewer iterations. This research highlights the potential of ML-driven approaches in accelerating material synthesis and optimization processes, paving the way for advances in two-dimensional (2D) material-based technologies.

Oxidation Behaviour of TiC/TiN Coatings Deposited by Chemical Vapor Deposition (CVD): Mechanisms, Structures, and Properties

This review explores the oxidation behavior of Titanium Carbide (TiC) and Titanium Nitride (TiN) coatings deposited by Chemical Vapor Deposition (CVD), with a focus on their industrial applications as wear-resistant coatings for cutting tools. It examines effect of process parameters—such as temperature, pressure, precursor composition, and substrate preparation—on formation and performance of TiC/TiN coatings. The review evaluates the microstructural characteristics of these coatings, including crystal structure, using X-ray diffraction analysis. Also, estimates the mechanical properties such as hardness, wear resistance, and adhesion strength. Additionally, the review covers the thermal stability of TiC/TiN coatings, emphasizing their ability to maintain structural integrity at high temperatures, which is essential for the performance of cutting tools and other industrial components. A major focus is the oxidation behavior of TiC/TiN coatings, including the impact of coating composition, deposition methods, and environmental conditions. The review details oxidation kinetics and mechanisms, revealing various stages of oxidation at different temperatures. It also examines oxide scale morphology and its effect on coating properties. Finally, this review reveals the importance of alloying elements, like silicon, in improving oxidation resistance. Composite coatings such as TiSiN and TiSiCN are shown to offer better high-temperature stability compared to traditional TiN coatings. The effects of coating thickness and the benefits of multilayer coatings for enhanced oxidation resistance are also discussed.

Dynamics of Nonlinear Optical Losses in Silicon‐Rich Nitride Nano‐Waveguides

AbstractFree carrier absorption (FCA) is established to be the cause of nonlinear losses in plasma‐enhanced chemical vapor deposition (PECVD) silicon‐rich nitride (SRN) waveguides. To validate this hypothesis, a photo‐induced current is measured in SRN thin films with refractive indices varying between 2.5 and 3.15 when a C‐band laser light is illuminating the SRN films at various powers, indicating the generation of free carriers. Furthermore, nonlinear loss dynamics is, for the first time, measured and characterized in detail in SRN waveguides by utilizing high peak power C‐band complex shape optical pulses for estimation of free carrier generation (FCG) and free carrier recombination (FCR) lifetimes and their dynamics. Both FCG and FCR are found to decrease with an increase in the refractive index of SRN, and, specifically, the FCR lifetimes are found (92 ± 7) ns, (39 ± 3) ns, and (31 ± 2) ns for the SRN indices of 2.7, 3, and 3.15, respectively. Lastly, nonlinear losses in high refractive index SRN waveguides are demonstrated to be minimized and altogether avoided when the pulse duration reduced below the free carrier generation lifetime, thus providing a way of taking a full advantage of the large inherent SRN nonlinear properties.