Rapid Thermal Treatment Research Articles

Enhancing negative thermal quenching in green-emitting perovskite microspheres via shallow trap state modulation

AbstractFor luminescent materials, negative thermal quenching (NTQ), characterized by an increase in the luminescent intensity with temperature, has a large potential in lighting and display technologies. However, leveraging NTQ in metal halide perovskites is challenging, and the mechanism is not well understood. Herein, by utilizing low-temperature photoluminescence, persistent luminescence and thermoluminescence, the origins of NTQ in CsPbBr3 microspheres are systematically studied, which pertain to the liberation of carriers from shallow trap states. Experimental and theoretical investigations reveal that the energy of these shallow defect states is approximately 0.135 eV beneath the conduction band. A rapid thermal treatment increases the density of these shallow traps and amplifies the NTQ effect, resulting in an enhancement of room-temperature photoluminescence by more than 60% compared to that at 150 K. The process also reduces the threshold for amplified spontaneous emission to about 45 W/cm2. Our findings not only provide a deeper understanding of the NTQ phenomenon in CsPbBr3 microspheres but also open new avenues for enhancing the performance of perovskite optoelectronic devices through energy state regulation.

Spatial Structure of Electron Interactions in High-entropy Oxide Nanoparticles for Active Electrocatalysis of Carbon Dioxide Reduction.

High-entropy oxides (HEOs) exhibit distinctive catalytic properties owing to their diverse elemental compositions, garnering considerable attention across various applications. However, the preparation of HEO nanoparticles with different spatial structures remains challenging due to their inherent structural instability. Herein, ultrasmall high-entropy oxide nanoparticles (less than 5nm) with different spatial structures are synthesized on carbon supports via the rapid thermal shock treatment. The low-symmetry HEO, BiSbInCdSn-O4, demonstrates exceptional performance for electrocatalytic carbon dioxide reaction (eCO2RR), including a lower overpotential, high Faraday efficiency across a wide electrochemical range (-0.3 to -1.6V), and sustained stability for over100h. In the membrane electrode assembly electrolyzer, BiSbInCdSn-O4 achieves a current density of 350mAcm-2 while maintaining good stability for 24h. Both experimental observations and theoretical calculations reveal that the electron donor-acceptor interactions between bismuth and indium sites in BiSbInCdSn-O4 enable the electron delocalization to facilitate the efficient adsorption of CO2 and hydrogenation reactions. Thus, the energy barrier of the rate-determining step is reduced to enhance the electrocatalytic activity and stability. This study elucidates that the spatial structure of metal sites in HEOs is able to regulate CO2 adsorption status for eCO2RR, paving the way for the rational design of efficient HEO catalysts.

Regeneration of Antifog Performance of Laser-Induced Copper-Based Micro-Nano Structured Surfaces by Rapid Thermal Treatment.

In this investigation, the laser marker ablation technique was employed on Cu-coated glass to fabricate micro-nanostructured antifog glass. The resulting surfaces exhibited a quasi-periodic micron hillock-hollow structure with dispersed nanoparticles distributed throughout, which played a role in the antifog property and superhydrophilicity. However, airborne organic pollutant deposition degraded the superhydrophilicity of ablated glass surfaces and, therefore, their antifog performance, which cannot be circumvented. Conventionally, furnace annealing for at least 1 h was used to decompose the organic pollutants and restore the superhydrophilicity, limiting the throughput and application scenario. Remarkably, the rapid regeneration of this property was achieved through either a 5 min rapid thermal treatment at 400 °C or a 1 s flame treatment. These are interventions that are hitherto unreported. Such short and simple treatment methods underscore the potential of laser-ablated glass for diverse practical applications.

Surface nitrogen defect modified crystalline carbon nitride spheres with boosted carrier dynamics for efficient solar hydrogen production

Engineering of the defective structure and crystallinity of semiconductor photocatalysts to promote carrier dynamics has attracted considerable attention. This study presents the design of surface nitrogen defect modified crystalline carbon nitride spheres (QCN) with synergistically boosted surface and bulk carrier separation through a rapid thermal treatment coupled with a flux assisted strategy. Using supramolecular self-assembled polymer as the precursor, spherical crystalline CN heterojunctions are firstly prepared by a molten salt method to improve the separation of bulk carriers. Abundant nitrogen defects are then introduced onto the surface of crystalline CN through the following quick thermal treatment in air, which can generate a higher exciton density and drive rapid migration of surface carriers by acting as effective electron sinks. Furthermore, the defect level also improves the visible light utilization and provides more active centers for reactant adsorption and activation. As a result, QCN samples exhibit excellent performance in photocatalytic hydrogen evolution, with an optimal hydrogen production rate 4.3 times higher than that of pristine bulk CN under visible light irradiation. Moreover, the photocatalytic activities of QCN are dependent on the concentration of nitrogen defects, which can be flexibly adjusted via thermal treatment temperature. Such a two-step regulation strategy combining the distinctive advantages of surface defect structure and high crystallinity is beneficial for synergistic enhancement of photocatalytic performance, and provides new insights for sustainable energy production in the future.

Structure of Silicon Wafers Planar Surface before and after Rapid Thermal Treatment

Presently it is important to remove mechanically disturbed layer on wafer surface during creation of up-to-date microelectronic products. Rapid thermal treatment with optical pulses of second duration is one of the applicable methods for removing disturbances in crystal lattice emerging after ion implantation. However the crystal structure of mechanically disturbed layer on wafer planar side is still unclear. Researches by transmission electronic method, analysis of diffraction reflection curve and electronic Auger spectroscopy has failed to provide reliable data about the state of crystal lattice in surface layer of at least 30 nm thickness. Hence it was impossible to suggest a model of solid phase recrystallization and to present its mathematical description. The goals of the work were as follows: – identify of silicon crystal lattice state in surface layer of 30 nm thickness before and after rapid thermal treatment by backward reflected electrons diffraction method using raw Si wafers surface; – analysis of contamination element composition on the surface of raw silicon before and after rapid thermal treatment; – model development for solid phase recrystallization of surface disturbed layer after rapid thermal treatment and its mathematical description. Images of back ward reflected electrons diffraction using surface layer of raw silicon wafers' of 30 nm thickness and also the results of the planar surface of raw silicon wafers' cleaning from impurities are provided. Processes reducing the activating energy of mechanically disturbed silicon layer recrystallization process were suggested and its mathematical description was provided. Parameters of rapid thermal treatment mitigating the thermal impact on silicon wafer for recrystallization of mechanically disturbed layer on its planar surface ware defined.

Impact Produced by Recrystallization of Mechanically Destroyed Layer on Planar Side of Silicon Wafer Upon Electrical Parameters of CMOS Microcircuits

The influence of recrystallization of a mechanically damaged layer on the working side of a silicon wafer using rapid heat treatment (1000 °C, 20 s) on the electrical parameters of complementary metal-oxide-semiconductor microcircuits has been established. The analyzed characteristics of n- and p-channel transistors were selected: drain current from the gate voltage when diode-connected; output characteristics at various gate voltages; drain current from the drain voltage without applying potential to the gate; percentage of yield of suitable products. These parameters were compared with microcircuits manufactured using standard technology. Analysis of the results showed that rapid thermal treatment of the original silicon wafers can significantly improve the above characteristics of n-channel metal-oxide-semiconductor ( n-MOS) and p-channel metal-oxide-semiconductor (p-MOS) transistors by reducing the fixed charge in gate dielectric obtained by pyrogenic oxidation of silicon. This makes it possible to improve the quality of manufactured complementary metal-oxide-semiconductor microcircuits and increase the percentage of yield of suitable products from 74.38 to 77.53 %.

Synthesis of Molybdenum Oxide Nanofibers with Multiple Surface Facets Via Electropsinning Followed by Rapid Thermal Treatment

A MoO3 nanofiber prepared by electrospinning and subsequent heat treatment is attracting significant attention due to its structural advantages. Vibrant studies are being conducted to control its morphology and diameter to improve its properties. In this study, we demonstrated the synthesis of α-MoO3 nanofibers with multiple surface facets by controlling the heating rate and temperature in the heat treatment step for removing polymer and crystallizing MoO3 from the electrospun polymer/precursor nanofibers. The analysis results show that the faster heating rate and higher heat treatment temperature in the thermal treatment process are more favorable for forming a shape in which particles with facet planes are connected. Finally, we observed the morphological change according to the heat treatment time to confirm the effect of the heat treatment conditions on the shape of MoO3 and interpreted the results in terms of nucleation and crystal growth.

Spin coating high‐k multicomponent (Al,Ti,V,Zr,Hf)Ox films with sub‐nm EOT for MOS‐based electronic devices

AbstractThe facile spin coating fabrication of high‐dielectric‐constant (high‐k) multicomponent (Al,Ti,V,Zr,Hf)Ox films with an equivalent oxide thickness of ≈0.95 nm and the investigation of their thermal stability and dielectric and electrical properties of the resulting advanced metal–oxide–semiconductor (MOS)‐based electronic devices are reported in this study. Various heating conditions, including drying following spin coating, annealing after drying, and forming gas annealing, were investigated to optimize the quality of the films and reduce film defects. The favorable film‐based MOS devices exhibited robust capacitance–voltage (C–V) and current–voltage (I–V) characteristics with a remarkable k value of approximately 62 at 1 kHz. The thermal stability of the films was affirmed through a rapid thermal annealing treatment at 900°C for 5 s and observation of nondegraded C–V and I–V curves. The electrical performance of the resulting MOS field‐effect transistors (MOSFETs), including a threshold voltage of 0.4 V, an on/off ratio of 106, a saturated mobility of 40.1 cm2 V−1 s−1, and a subthreshold swing of 66.7 mV dec−1, was obtained. Moreover, hole‐ and electron‐trapping measurements through negative and positive gate bias stress instabilities, respectively, indicate the reliable performance of our MOSFETs. Our results imply that solution‐based processes are promising for fabricating fundamental semiconductor devices.

Microstructure and Properties of Thin-Film Submicrostructures Obtained by Rapid Thermal Treatment of Nickel Films on Silicon

Nickel films of 40 nm thickness were obtained by means of magnetron sputtering on a single-crystalline silicon substrate. The films were subjected to rapid thermal treatment (RTT) for 7 s until the temperature increased from 200 to 550 °C. By means of the X-ray diffraction method, the structural-phase composition of nickel films before and after RTT was explored. The atomic force microscopy method due to direct contact with the surface under study, made it possible to accurately define the microstructure, roughness, specific surface energy and grain size of the nickel films before and after RTT, as well as to establish the relationship of these parameters with the phase composition and electrical properties of the films. Surface specific resistance was measured using the four-probe method. Based on XRD results, formation of Ni2Si and NiSi phases in the film was ascertained after RTT at 300 °C. At RTT 350–550 °C, only the NiSi phase was formed in the film. The microstructure and grain size significantly depend on the phase composition of the films. A correlation has been established between specific surface energy and resistivity with the average grain size after RTT at 350–550 °C, which is associated with the formation and constant restructuring of the crystal structure of the NiSi phase.

Rapid Thermal Treatment of Oriented Microstructures to Generate Fine Globular Grains

Rapid Thermal Treatment of Oriented Microstructures to Generate Fine Globular Grains

Effect of rapid thermal annealing treatment on up-conversion luminescence in Er3+/Yb3+ co-doped NaYF4 oxy-fluoride glass-ceramics

The heat-treatment plays a decisive role in the process of crystal phase precipitation and the microscopic features of the fluoride particles, which determines the optical transmittance and up-conversion luminescence (UCL) properties. In this work, we successfully synthesized Er3+/Yb3+ co-doped UCL transparent oxy-fluoride glass-ceramics (GCs) by precipitation of NaYF4 nanoparticles using a rapid thermal annealing (RTA) treatment with ultra-high heating rate (100 K/s). The particle sizes of NaYF4 nanoprecipitation inside glass-ceramic is only 4–5 nm, which is much smaller than the 40–50 nm particle sizes obtained using normal-heating treatment. The GCs with ultra-small particle sizes provided a very high optical transmittance that is close to that of all-amorphous glass, but the intensity of UCL was similar to that of a sample prepared using a slower heating rate. Finally, under different heat treatment conditions the Er3+/Yb3+ co-doped NaYF4 transparent GCs with different particle sizes can be produced, the color and intensity of UCL were controllable.

Temperature Dependence of 3С-SiC Growth During Rapid Vacuum Thermal Silicon Treatment

The paper presents the results of a study of the structure, phase composition, and growth kinetics of silicon carbide epitaxial layers on silicon substrates during their rapid vacuum thermal treatment. Transmission electron microscopy revealed the formation of layers of the cubic polytype SiC (3C-SiC) on silicon during carbidization in the temperature range of 1000–1300 °C. It was found that the formation of SiC layers proceeds in two stages, characterized by different activation energies. In the lower temperature range from 1000 to 1150 °C, the activation energy of the SiC growth process is Ea = 0.67 eV, while in the temperature range from 1150 to 1300 °C, the activation energy increases by almost an order of magnitude (Ea = 6.3 eV), which indicates a change in the limiting physical process. It has been established that the type of conductivity and the orientation of the substrate affect the thickness of the formed SiC layers. In this case, the greatest thickness of silicon carbide layers is achieved on silicon substrates with (111) orientation of p-type conductivity.

Boosting the Self-Trapped Exciton Emission in Cs4SnBr6 Zero-Dimensional Perovskite via Rapid Heat Treatment.

Zero-dimensional (0D) tin halide perovskites feature extraordinary properties, such as broadband emission, high photoluminescence quantum yield, and self-absorption-free characteristics. The innovation of synthesis approaches for high-quality 0D tin halide perovskites has facilitated the flourishing development of perovskite-based optoelectronic devices in recent years. However, discovering an effective strategy to further enhance their emission efficiency remains a considerable challenge. Herein, we report a unique strategy employing rapid heat treatment to attain efficient self-trapped exciton (STE) emission in Cs4SnBr6 zero-dimensional perovskite. Compared to the pristine Cs4SnBr6, rapid thermal treatment (RTT) at 200 °C for a duration of 120 s results in an augmented STE emission with the photoluminescence (PL) quantum yield rising from an initial 50.1% to a substantial 64.7%. Temperature-dependent PL spectra analysis, Raman spectra, and PL decay traces reveal that the PL improvement is attributed to the appropriate electron-phonon coupling as well as the increased binding energies of STEs induced by the RTT. Our findings open up a new avenue for efficient luminescent 0D tin-halide perovskites toward the development of efficient optoelectronic devices based on 0D perovskites.

Controllably partial removal of thiolate ligands from unsupported Au25 nanoclusters by rapid thermal treatments for electrochemical CO2 reduction

Colloidal synthesis of metal nanoclusters will inevitably lead to the blockage of catalytically active sites by organic ligands. Here, taking [Au25(PET)18]− (PET = 2-phenylethanethiol) nanocluster as a model catalyst, this work reports a feasible procedure to achieve the controllably partial removal of thiolate ligands from unsupported [Au25(PET)18]− nanoclusters with the preservation of the core structure. This procedure shortens the processing duration by rapid heating and cooling on the basis of traditional annealing treatment, avoiding the reconfiguration or agglomeration of Au25 nanoclusters, where the degree of dethiolation can be regulated by the control of duration. This work finds that a moderate degree of dethiolation can expose the Au active sites while maintaining the suppression of the competing hydrogen evolution reaction. Consequently, the activity and selectivity towards CO formation in electrochemical CO2 reduction reaction of Au25 nanoclusters can be promoted. This work provides a new approach for the removal of thiolate ligands from atomically precise gold nanoclusters.

Improvement of Supercapacitor Performance of In Situ Doped Laser-Induced Multilayer Graphene via NiO.

Herein, we have reported a novel strategy for improving the electrochemical performance of laser-induced graphene (LIG) supercapacitors (SCs). The LIG was prepared using a CO2 laser system. The polyimide polymer was the source material for the fabrication of the LIG. The doping process was performed in situ using the CO2 laser, which works as a rapid thermal treatment to combine graphene and NiO particles. NiO was used to improve the capacitance of graphene by combining an electric double-layer capacitor (EDLC) with the pseudo-capacitance effect. The high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy, and Raman spectroscopy showed that the structure of the LIG is multilayered and waved. The HRTEM image proves the distribution of NiO fine particles with sizes of 5-10 nm into the graphene layers. The electrochemical performance of the as-prepared LIG was tested. The effect of the combination of the two materials (oxide and carbon) was investigated at different concentrations. The LIG showed a specific capacitance of 69 Fg-1, which increased up to 174 Fg-1 for the NiO-doped LIG. The stability investigations showed that the electrodes were very stable for more than 1000 cycles. This current study establishes an innovative method to improve the electrochemical properties of LIG.

Enhanced emission from hBN in sputtered microcavities.

In this observational study, we embed few-layer hexagonal boron nitride (hBN) inside a planar Fabry-Perot cavity fabricated using a pulsed DC magnetron sputtering system and show that the hBN retains its inherent visible range, defect-based luminescent properties following relatively energetic deposition processing. The observed surface-normal emission enhancement factor of ∼40 is in good agreement with theoretical predictions. We also found that embedded hBN subjected to a rapid thermal annealing treatment exhibits a cracking effect where the edges of the material glow distinctly brighter than adjacent regions. Our results might inform future efforts involving monolithic integration of hBN active layers.

Synthesis and Improved Photoluminescence of SnF2-Derived CsSnCl3-SnF2:Mn2+ Perovskites via Rapid Thermal Treatment.

We report a rapid synthesis method for producing CsSnCl3:Mn2+ perovskites, derived from SnF2, and investigate the effects of rapid thermal treatment on their photoluminescence properties. Our study shows that the initial CsSnCl3:Mn2+ samples exhibit a double luminescence peak structure with PL peaks at approximately 450 nm and 640 nm, respectively. These peaks originate from defect-related luminescent centers and the 4T1→6A1 transition of Mn2+. However, as a result of rapid thermal treatment, the blue emission is significantly reduced and the red emission intensity is increased nearly twofold compared to the pristine sample. Furthermore, the Mn2+-doped samples demonstrate excellent thermal stability after the rapid thermal treatment. We suggest that this improvement in photoluminescence results from enhanced excited-state density, energy transfer between defects and the Mn2+ state, as well as the reduction of nonradiative recombination centers. Our findings provide valuable insights into the luminescence dynamics of Mn2+-doped CsSnCl3 and open up new possibilities for controlling and optimizing the emission of rare-earth-doped CsSnCl3.

Ge-ion implantation and activation in (100) β-Ga2O3 for ohmic contact improvement using pulsed rapid thermal annealing

In this work, we analyze the optimum annealing conditions for the activation of Ge-implanted β-Ga2O3 in order to reach low ohmic contact resistances. The experiments involved the use of a pulsed rapid thermal annealing treatment at temperatures between 900 and 1200 °C in nitrogen atmosphere. Our investigations show remarkable changes in the surface morphology involving increased surface roughness after high-temperature annealing above 1000 °C as well as a significant redistribution of the implanted Ge. Nevertheless, the specific contact resistance is strongly reduced by one order of magnitude after annealing at 1100 °C, reaching a record value of 4.8 × 10−7 Ω cm2 at an implantation activation efficiency of 14.2%. The highest activation efficiency of 19.2% and lowest sheet resistances were reached upon annealing at 1200 °C, which, in turn, showed inferior ohmic contact properties due to a severe increase of the surface roughness. Our results verify the high potential of applying high-temperature annealing processes above 1000 °C after Ge implantation for reaching low ohmic contact resistances to β-Ga2O3.

Activation of Mg impurities in epitaxial p-GaN with rapid thermal annealing assisted supercritical fluid treatment

The activation of an Mg acceptor in p-GaN with rapid thermal annealing (RTA) assisted low-temperature supercritical fluid (SCF) treatment (RTA-A-SCF) was investigated. After RTA-A-SCF treatment, the luminescence band of the N vacancy in the PL spectra was significantly suppressed. An evident decrease in H concentration is also observed in secondary ion mass spectrometer measurements, it indicates an obvious decrease of Mg–H complexes in the p-GaN. In addition, the ohmic contacts have been well improved and the hole concentration has increased by an order of magnitude. The activation mechanism of RTA-A-SCF treatment was further analyzed by X-ray photoelectron spectroscopy.

Fabrication of thin ferroelectric Hf0.5Zr0.5O2 films by millisecond flash lamp annealing

We used millisecond flash lamp annealing (FLA) to form thin ferroelectric Hf0.5Zr0.5O2 (HZO) films with thicknesses of less than 10 nm and with remanent polarization up to 30 μC cm−2. A clear dependency of the polarization on the annealing temperature and time was observed, indicating that the precise management of the thermal budget is a key factor in forming ferroelectric HZO. We also show and compare the process windows within which ferroelectricity in 10 and 5 nm samples is obtained. The results show that a high thermal budget is necessary for thinner samples. We examined the endurance characteristics and a greater endurance compared to rapid thermal annealing treatment was observed with more than 1010 cycles without breakdown confirmed in 5 nm thick samples. The data indicates that there is the possibility of further thickness scaling whilst retaining highly durable characteristics for films annealed by FLA.