Photoluminescence Peak Research Articles

Carbon dots with high brightness and stability towards efficient Cr(Ⅵ) and l-arginine sensors

To create fluorescent sensors for Cr (VI) and l-arginine detection, blue-emitting carbon dots (CDs, named as M-CDs) were prepared via a solvothermal synthesis by using m-phenylenediamine. The introduction of sulfuric acid changed the blue-emitting of CDs into green-emitting (named as S-CDs), in which the photoluminescence (PL) peak wavelengths of samples M-CDs and S-CDs were 450 and 540 nm, while their PL efficiencies were 21.7 and 84.2 % respectively. Sulfuric acid resulted in the average fluorescent lifetime of the CDs was prolonged into 8.19 from 4.65 ns. The photo and thermal stable tests demonstrated that theses CDs revealed excellent stability. Meanwhile, CDs flexible films with bright blue- and green-emitting were prepared utilizing the favorable solubility of CDs in polar solvents. Mono-dispersed CDs as luminescent materials demonstrated it promising prospects in luminescent devices field. Furthermore, M-CDs exhibited excellent selectivity towards Cr(Ⅵ) and l-arginine. The detected limit (0.86 μM for Cr(Ⅵ) and 0.43 μM for l-arginine) was determined by assessing the response of M-CDs to various concentrations of Cr(Ⅵ) ion and l-arginine solutions. These bright CDs revealed great potential for accurate detection of Cr(Ⅵ) and l-arginine.

Substrate-induced strain upshot on the optical and optoelectronic properties of trilayer MoS2.

The characteristics of 2D layered MoS2 film are highly dependent on the substrate it is grown on which leaves us privileged to achieve unique and tunable properties. In this study, trilayer MoS2 films have been grown on fused quartz, crystalline quartz (z-cut), sapphire (0001), and silicon (100) substrates. MoS2 film grows as freestanding on amorphous fused quartz, while it experiences an in-plane tensile strain on the sapphire and silicon. Unprecedentedly we show that due to a large mismatch in the lattice parameter as well as in the thermal expansion coefficient, MoS2 grows with a significant compressive strain both along both in-plane on the crystalline quartz. The developed strain causes an alteration in its electronic structure, causing a 30 meV blue shift in the photoluminescence peak and an increased band gap in addition to fewer sulphur vacancies. Comparatively, the film on sapphire having tensile strain along the in-plane exhibits more sulphur vacancies increasing the electron density. The photoresponse time, photosensitivity, and charge separation distinctly vary for the MoS2 films depending on the substrates. This study underscores the influence of substrate on MoS2 film opening further research scopes on tunable properties owing to 2D layer-substrate interactions.

Stabilizing Metal Halide Perovskite Films via Chemical Vapor Deposition and Cryogenic Electron Beam Patterning.

Halide perovskites are hailed as semiconductors of the 21st century. Chemical vapor deposition (CVD), a solvent-free method, allows versatility in the growth of thin films of 3- and 2D organic-inorganic halide perovskites. Using CVD grown methylammonium lead iodide (MAPbI3) films as a prototype, the impact of electron beam dosage under cryogenic conditions is evaluated. With 5 kV accelerating voltage, the dosage is varied between 50 and 50000 µC cm-2. An optimum dosage of 35 000 µC cm-2 results in a significant blue shift and enhancement of the photoluminescence peak. Concomitantly, a strong increase in the photocurrent is observed. A similar electron beam treatment on chlorine incorporated MAPbI3, where chlorine is known to passivate defects, shows a blue shift in the photoluminescence without improving the photocurrent properties. Low electron beam dosage under cryogenic conditions is found to damage CVD grown 2D phenylethlyammoinum lead iodide films. Monte Carlo simulations reveal differences in electron beam interaction with 3- and 2D halide perovskite films.

Microwave assisted synthesis of ErxYbyCa1-x-yMoO4 nano-phosphor for efficient temperature sensing and catalytic applications

Here, Er/Yb Co-doped CaMoO4 materials (ErxYbyCa1−x−yMoO4 NPs where x = 0, 0.01 and y = 0, 0.05, 0.10, 0.15, 0.20) were prepared by microwave-assisted method and its pure-tetragonal structure were confirmed by X-ray diffraction spectra (XRD), Rietveld-refinement and Raman-vibrational spectra. The transmission-electron microscopy (TEM) study indicates the formation of nearly spherical shaped nanomaterial with average size of ~ 15 nm. Additionally, absorption and emission properties were studied by UV–Visible–NIR and photoluminescence (PL) spectrometer. The UV–Visible–NIR spectra attribute absorption of Er3+ ion in visible region (380–700 nm) and absorption of Yb3+ ion in near-infrared region (700–1400 nm). Moreover, PL up-conversion spectra of the sample recorded under excitation wavelength 980 nm. The PL peaks were observed at 530, 544–552, and 656–670 nm. Prominent PL-intensity was observed for Er0.01Yb0.15Ca0.84MoO4 phosphor. Temperature dependent PL study reveals that present phosphor is robust phosphor for temperature sensor. In addition, Er3+/Yb3+ doped CaMoO4 nanomaterials exhibited excellent activity and selectivity in the aerial oxidation of benzoin over benzyl under oxidant-free reaction conditions. The synergistic effect Er3+/Yb3+ co-doing in CaMoO4 matrix was observed, where only CaMoO4 material found to be inactive towards above oxidation reaction. Moreover, the oxidation of primary benzyl-alcohols was furnished in presence of tertiary butyl hydroperoxideas oxidant.

Homoepitaxial growth of device-grade GaAs using low-pressure remote plasma CVD

We have achieved the growth of high-quality, homoepitaxial 100 GaAs thin films at 0.5 mbar and 500 °C using a Remote Plasma Chemical Vapor Deposition (RP-CVD) reactor. With this process, we demonstrate a film growth rate up to 3 μm/h, comparable to the conventional MOCVD technique. The resulting films exhibit structural characteristics close to those of commercial GaAs wafers, with excellent crystalline quality as confirmed by SAED patterns and XRD rocking-curve measurements for the 004 peak with a FWHM of 0.004°. AFM measurements reveal a surface roughness of 0.2 nm, similar to that of a polished wafer. Analysis of the chemical composition – as determined through XPS surface and depth-profiled measurements – indicates that the film is homogeneous, with a constant III/V ratio of 1 throughout the whole layer, and has no detectable carbon or oxygen contamination. Additionally, the films demonstrate a sharp photoluminescence peak (FWHM of 55 meV), a p-type doping concentration of 1.1018 cm−3, and a hole mobility of 172 cm2 V⁻1.s⁻1. This work thus demonstrates a cost-effective growth method for III-V devices, enabled by the reduced gas consumption (only a few sccm, compared to tens of L/min in MOCVD) in RP-CVD operation at low pressure.

Violet Perovskite Quantum Dots of MA3Bi2Br9 and MA3Bi2Br6Cl3 Synthesized by the Cb‐LARP Method with Tunable Emission Wavelengths in Range of 379–400 nm

AbstractViolet‐emitting perovskite quantum dots (QDs) are of great significance for theoretical and experimental research aimed at promoting the development of environmentally friendly violet light‐emitting diodes (LEDs). Nevertheless, the synthesis of violet perovskite QDs via ligand‐assisted reprecipitation is challenging due to the significant bandgap. A simple and economical cryo‐bonding ligand‐assisted reprecipitation (Cb‐LARP) method is proposed as a means of synthesizing deep violet lead‐free organic‐inorganic hybrid perovskite (OIHP) QDs, with the objective of increasing the bandgap in the material. The MA3Bi2Br9 QDs synthesized by the Cb‐LARP method exhibit bright violet luminescence at 400 nm, with a PLQY of 50.1%. Moreover, the photoluminescence peak of the QDs can be adjusted from 402 to 393 nm by modifying the final reaction time. It is noteworthy that the MA3Bi2Br6Cl3 QDs exhibited ultraviolet emission at 379 nm, corresponding to a PLQY of 35.4%. Similarly, the emission peak of the QDs can be tuned from 379 to 376 nm by changing the final reaction time. The results demonstrate that the deep violet emitting OIHP QDs have been successfully synthesized. This study provides a theoretical reference for short‐wavelength perovskite materials and an experimental reference for the study of violet and UV quantum‐dot light‐emitting diode devices.

Molecular beam epitaxial growth and physical properties of AlN/GaN superlattices with an average 50% Al composition

Abstract We report molecular beam epitaxial growth and electrical and ultraviolet light emitting properties of (AlN)m/(GaN)n superlattices (SLs), where m and n represent the numbers of monolayers. Clear satellite peaks observed in XRD 2θ-ω scans and TEM images evidence the formation of clear periodicity and atomically sharp interfaces. For (AlN)m/(GaN)n SLs with an average Al composition of 50%, we have obtained an electron density up to 4.48×1019 cm-3 and a resistivity of 0.002 Ω·cm, and a hole density of 1.83×1018 cm-3 with a resistivity of 3.722 Ω·cm, both at room temperature. Furthermore, the (AlN)m/(GaN)n SLs exhibit a blue shift for their photoluminescence peaks, from 403 nm to 318 nm as GaN reduced from n=11 to n=4 MLs, reaching the challenging UVB wavelength range. The results demonstrate that the (AlN)m/(GaN)n SLs have the potential to enhance the conductivity and avoid the usual random alloy scattering of the high-Al-composition ternary AlGaN, making them promising functional components in both UVB emitter and AlGaN channel high electron mobility transistor applications.

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.

Förster Resonance Energy Transfer and Enhanced Emission in Cs4PbBr6 Nanocrystals Encapsulated in Silicon Nano-Sheets for Perovskite Light Emitting Diode Applications.

Encapsulating Cs4PbBr6 quantum dots in silicon nano-sheets not only stabilizes the halide perovskite, but also takes advantage of the nano-sheet for a compatible integration with the traditional silicon semiconductor. Here, we report the preparation of un-passivated Cs4PbBr6 ellipsoidal nanocrystals and pseudo-spherical quantum dots in silicon nano-sheets and their enhanced photoluminescence (PL). For a sample with low concentrations of quantum dots in silicon nano-sheets, the emission from Cs4PbBr6 pseudo-spherical quantum dots is quenched and is dominated with Pb2+ ion/silicene emission, which is very stable during the whole measurement period. For a high concentration of Cs4PbBr6 ellipsoidal nanocrystals in silicon nano-sheets, we have observed Förster resonance energy transfer with up to 87% efficiency through the oscillation of two PL peaks when UV excitation switches between on and off, using recorded video and PL lifetime measurements. In an area of a non-uniform sample containing both ellipsoidal nanocrystals and pseudo-spherical quantum dots, where Pb2+ ion/silicene emissions, broadband emissions from quantum dots, and bandgap edge emissions (515 nm) appear, the 515 nm peak intensity increases five times over 30 min of UV excitation, probably due to a photon recycling effect. This irradiated sample has been stable for one year of ambient storage. Cs4PbBr6 quantum dots encapsulated in silicon nano-sheets can lead to applications of halide perovskite light emitting diodes (PeLEDs) and integration with traditional semiconductor materials.

Hexagonal Enhanced Porous GaN with Delayed Integrated Pulse Electrochemical (iPEC) Etching

This present study investigates the effect of time delay (Td) on the formation of porous GaN (P-GaN) using integrated pulse electrochemical (iPEC) etching. Porous GaN (P-GaN) was formed by etching an N-type GaN wafer with a 4% KOH electrolyte for 60 minutes under an ultraviolet (UV) lamp at a current density of 80 mA/cm2. A Td of 120 minutes was applied before electrochemically etching the P-GaN sample. The top view image of the field emission scanning electron microscopy (FESEM) revealed a significant difference when a Td was applied. A dense and uniform hexagonal P-GaN was obtained from the Td iPEC sample, while the non-Td sample exhibited a multi-layered hexagonal porous structure with unfinished pore-etched areas. Higher porosity and deeper pores were observed in the Td sample. Intense high-resolution X-ray diffraction (HR-XRD) peak intensity was observed in the Td iPEC sample with a lower full width half maximum (FWHM), indicating that the sample had better crystallinity. The Raman spectra of the sample anodized with a Td exhibited higher Raman peak intensity and a slight shift to a higher frequency concerning as-grown GaN, indicating better crystallinity and a tensile stress relaxation of 0.24 GPa. Post etching, a blue shift of the photoluminescence (PL) peak, from 364 nm (as-grown GaN) to 363 nm (P-GaN), was observed, and a small PL peak started to form around 385 nm compared to the as-grown GaN due to the relaxation of the tensile stress, which modified the bandgap. The PL peak intensity of the Td sample was higher than the non-Td sample, indicating that the porosity and uniformity allowed more light interaction with the material, resulting in more efficient photon absorption and emission. The results indicated that potentially efficient optoelectronics devices can be fabricated on a P-GaN using a combination of electroless and electrochemical etching of the GaN epitaxial layer.

Modulation of photoluminescence properties of transition metal dichalcogenides through temperature and Au/Ag nanoparticles

Abstract Transition metal dichalcogenides (TMDCs) attract significant attention because of their remarkable optical properties. Nowadays, the light emission efficiency of TMDCs is still inferior. Temperature and plasma resonance effects can be important approaches in the modulation of their luminescence performance. Here, multilayer WSe2 and monolayer MoSe2 were synthesized. Under the temperature control system, two photoluminescence (PL) peaks are observed from multilayer WSe2. The higher-energy PL peak results from K-Γ indirect band gap transition, which is then demonstrated by the first principle calculation. Otherwise, PL enhancement is realized on monolayer MoSe2 decorated with Au nanoparticles. The PL of WS2 is inhibited by hybridization with Ag nanoparticles.

Non-thermal atmospheric jet plasma effects on the morphological, electrical and optical properties of nanocrystalline silicon

In this study, a non-thermal atmospheric argon plasma jet (NTAPJ) was designed and used to treat the porous silicon layer, prepared by photoelectrochemical etching (PECE). The porous silicon layers were distinguished before and after the cold plasma treatment utilized by X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), photoluminescence (PL), and dark and photo current-voltage characteristics. The results confirmed the nanostructure of the formed porous silicon. After the treatment with argon plasma, the intensity of the XRD peak increased, and the porosity decreased from 93% to 62%. Additionally, porous silicon's average roughness (Sa) and root mean square (Sq) were reduced from 60.10 to 12.31nm and 73.70 to 16.53nm, respectively. The current-voltage characteristic indicated the increase in photocurrent and the ideality factor, as well as a decrease in dynamic resistance. The photoluminescence results showed a change in PL peaks, represented by a blue shift, an increase in intensity, and a vanishing of another peak.

Non-thermal atmospheric jet plasma effects on the morphological, electrical and optical properties of nanocrystalline silicon

In this study, a non-thermal atmospheric argon plasma jet (NTAPJ) was designed and used to treat the porous silicon layer, prepared by photoelectrochemical etching (PECE). The porous silicon layers were distinguished before and after the cold plasma treatment utilized by X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), photoluminescence (PL), and dark and photo current-voltage characteristics. The results confirmed the nanostructure of the formed porous silicon. After the treatment with argon plasma, the intensity of the XRD peak increased, and the porosity decreased from 93% to 62%. Additionally, porous silicon's average roughness (Sa) and root mean square (Sq) were reduced from 60.10 to 12.31nm and 73.70 to 16.53nm, respectively. The current-voltage characteristic indicated the increase in photocurrent and the ideality factor, as well as a decrease in dynamic resistance. The photoluminescence results showed a change in PL peaks, represented by a blue shift, an increase in intensity, and a vanishing of another peak.

Effects of off-axis angles of 4H-SiC substrates on properties of β-Ga2O3 films grown by low-pressure chemical vapor deposition

In this work, β-Ga2O3 films with (−201) preferred orientation were heteroepitaxially grown on SiC substrates with off-axis angles of 0°, 4° and 8° by low-pressure chemical vapor deposition (LPCVD). It is found that the crystal quality, surface morphology, electrical properties of the β-Ga2O3 films of the film are significantly sensitive to the off-axis angle of SiC substrates. The crystal quality and surface morphology of the film were significantly improved when the 4° off-axis substrate was used, of which the FWHM (Full width at half maximum) was as low as 0.169° and the Ra (Roughness Average) of the smooth surface was 1.98 nm. Due to the improvement of crystal quality, the Hall mobility of the films deposited on 4° off-axis substrates was increased to 50.88 cm2/V·s. The photoluminescence peak intensity of the film increases first and then decreases with the increase of the off-axis angle of the substrate. However, the use of the off-axis substrate has no obvious effect on the oxygen vacancy ratio of the films. The results of this study demonstrate the significance for the preparation of high quality heteroepitaxial β-Ga2O3 films on SiC substrate for the promising applications in power electronic and optoelectronic devices.

Properties of phosphorus-boron co-doped c-Si quantum dots/SiNx:H thin film prepared by PECVD in-situ deposition

Co-doping of phosphorus and boron elements into crystalline silicon quantum dot (c-Si QD) is an effective approach for enhancing the photoluminescence (PL) performance. In this paper, we report on the preparation of hydrogenated silicon nitride (SiNx:H) thin films embedded with phosphorus-boron co-doped c-Si QDs via plasma enhanced chemical vapor deposition route. Mixed dilution including hydrogen (H2) and argon (Ar) is applied in the in-situ deposition process for optimizing the deposition process. The P-B co-doped c-Si QD/SiNx:H thin films exhibit a wide range of PL spectra. The emission is greatly improved especially for the short-wavelength light when compared to the SiOx:H thin film containing P-B co-doped c-Si QDs. The effects of H2/Ar flow ratio on the structural and optical characteristics of thin films are systematically investigated through a series of characterizations. Experimental results show that various properties, such as crystallinity, QD size, optical band gap and doping concentrations, are effectively controlled by tuning H2/Ar flow ratio. Based on the red-shift of QCE-related PL peak, the successful P-B co-doping into Si QDs are verified. Finally, a comprehensive discussion has been made to analyze the influence of H2-Ar mixed dilution on the film growth and impurity doping in detail in this paper.

On the response of the CR-39 NTD to low doses of gamma rays using optical and photoluminescence spectroscopy

In this work, the response of the CR-39 nuclear track detector (NTD) exposed to different low doses of gamma rays was investigated using UV–Vis and photoluminescence spectroscopy. Five NTDs of CR-39 were irradiated with low gamma-ray doses ranging from 10 to 120 kGy using a60Co source. The dose of gamma rays correlates with red shift in the absorption spectra of a gamma-irradiated CR-39 detector. As the gamma dose increases, the indirect and direct energy band gaps, as well as Urbach energy, decrease gradually. However, the decrease in the indirect optical band gap is greater than the decrease in the direct band gap. The observed spectra of the CR-39 detector after being irradiated with different doses of γ-rays showed an acceptable variation in photoluminescence (PL) emission spectra generated by a well-defined excitation wavelength of 290 nm. Starting at 45 kGy dose, the integrated area of the photoluminescence peak increases and tends to saturate, whereas the photoluminescence peak height is linearly correlated with the gamma dose with high sensitivity, which is 53.1 ± 6.3 CPS. kGy−1. According to the current findings, photoluminescence (PL) spectroscopy has a greater sensitivity than UV–Vis spectroscopy for measuring the response of the CR-39 detector to gamma rays in the dose range of 10–120 kGy. The results reflected a potential possibility of using the CR-39 detector in dosimetric applications of low gamma ray doses through the high resolution achieved by photoluminescence (PL) and UV–Vis spectroscopy.

CsPb(Br/Cl)3-Sm3+ codoped glasses for optical temperature sensing in FIR and chromatic coordinate modes

We have fabricated Sm3+ doped glasses, CsPb(Br/Cl)3 quantum dots (QDs) glasses and CsPb(Br/Cl)3-Sm3+ codoped glasses by melt-quenching and subsequent heat treatment for optical temperature sensing. Photoluminescence (PL), photoluminescence excitation (PLE) spectra and PL decay have been measured. Two CsPb(Br/Cl)3-Sm3+ samples with different PL peaks of QDs at 486 nm and 503 nm have been studied for fluorescence intensity ratio (FIR) and chromatic coordinate sensing. The CsPb(Br/Cl)3 QDs and Sm3+ ions exhibit distinguished spectral components and they are dynamically independent. PL intensity of QDs rapidly decreases with temperature, whereas PL intensity of Sm3+ slowly decreases with temperature. PL intensity of Sm3+ ions and CsPb(Cl/Br)3 QDs have been independently fitted. Then, FIR sensing has been studied. The different variation in PL intensity with temperature for Sm3+ and CsPb(Cl/Br)3 leads to the change of luminescent color and chromatic coordinate. The chromatic coordinate sensing has also been studied. Absolute sensitivity (Sa) and relative sensitivity (Sr) have been analyzed for both FIR and chromatic coordinate sensing. Compared with the chromatic coordinate mode, FIR mode has the larger Sa and Sr. But the chromatic coordinate method is more convenient for application, which does not require separating two spectral components. Both FIR and chromatic coordinate sensing modes show outstanding temperature cycling characteristics.

Improvement on the onset voltage for electroluminescent devices based in a SiOx/SiOy bilayer obtained by sputtering

Abstract This work is focused on the composition, optical and electroluminescent properties of silicon rich oxide (SiOx, x < 2) films monolayers and bilayers (SiOx/SiOy) deposited by Sputtering with silicon excess between 6.2 to 10.7 at.% were deposited on p-type (100) silicon substrates. As-deposited SiOx films emit a broad photoluminescence (PL) band where the maximum peak shifts from 420 to 540 nm as the Si-excess increases from 6.2 to 10.7 at.%, respectively. The PL intensity strongly increases and the main PL peak shifts to the red region when the SiOx films are thermally annealed. The PL emission band was dependent on silicon excess and the presence of Si-O bonds defects working as emission centers. MOS-like devices were fabricated (N+ polysilicon was used as top contact and aluminum as bottom contact) to study the EL of SiOx monolayers and SiOx/SiOy bilayers. It was found that the required voltage to obtain EL was reduced when SiOx/SiOy bilayers were used in light emitting capacitors (BLECs) as compared to those with SiOx monolayers.

Structure and optical properties of ZnxCd1-xS and Cu:ZnxCd1-xS templated on DNA molecules

One-dimensional ZnxCd1−xS and Cu: Zn x Cd1−x S nanostructures were prepared using DNA as a template to promote growth along the molecular axis. The formation of homogeneously alloyed nanocrystals with cubic zinc blende-type structures was verified using x-ray diffraction and Raman spectroscopy. X-ray photoemission spectra revealed the presence of Cu(I) in the doped Cu: Zn x Cd1−x S nanocrystals. The effectiveness of the DNA template to direct the semiconductor growth in one dimension was demonstrated by AFM and TEM. The nanostructures displayed a granular morphology comprising nanoparticles with an average diameter of 14 nm composed of assemblies of smaller crystallites of 2.0 nm in size. Rope-like assemblies with an average diameter of 48 nm and extending in length to several hundred micrometres were obtained by evaporation-induced self-assembly. UV-Vis absorption and emission spectra indicated that the optical bandgaps (2.89–4.00eV) and photoluminescence peaks (608–819 nm) of the DNA-templated nanocrystals could be precisely controlled by modifying the molar ratios of their Zn/Cd precursors. Doping with Cu(I) gave an increase in photoluminescence intensity and a composition-independent red-shift of 0.23 eV. The preparation of DNA-templated Zn x Cd1−x S and Cu: Zn x Cd1−x S provides a simple, low-temperature route to aqueous dispersions of inorganic materials with controlled optical gap.

Effect of Fe2O3 addition on synthesis of diamond single crystal under high-pressure and high-temperature conditions

The influence of Fe2O3 addition on the growth characteristics of synthetic diamonds under high-temperature and high-pressure conditions was systematically investigated in this work. Utilizing Fe2O3 as an oxygen source within the Fe-Ni-C-O system, oxygen-containing diamond single crystals were synthesized. The role of the oxygen atoms during the growth of large-sized diamonds with the {111} face as the growth surface was also analyzed. In addition, the morphology, growth rate, internal nitrogen content, and crystal quality of the crystals were examined. From our analysis, it was demonstrated that an increase in Fe2O3 addition leads to a reduction in the size of the synthetic crystals and a gradual decrease in the growth rate. The diamonds with complete crystal forms exhibited no significant change in color, and all appeared yellow. When the addition exceeded a threshold, cracks appeared around the seed crystal at about 0.3 mm, resulting in a cracked crystal phenomenon. A further increase in the Fe2O3 addition resulted in the skeleton crystal, and the crystal color turned black. Fourier Transform Infrared Spectroscopy (FTIR) measurements were also conducted, indicating that the introduction of oxygen atoms increases the nitrogen content in the crystals, which in turn aggregates in the form of C-centered nitrogen. The Raman spectroscopy results showed that as Fe2O3 addition in the crystals increases, more impurities are introduced, leading to an increase in the diamond stress and a shift in the diamond Raman peak, along with an increase in the full width at half maximum. The photoluminescence (PL) characterization results indicated that with the increase of the Fe2O3 addition, the intensity of the photoluminescence peaks of NV− centers and W8 centers was enhanced, which is related to the increase in the internal C-centered nitrogen content of the crystals. From the acquired results, it was proven that Fe2O3 addition has a significant impact on the synthesis of diamond single crystals. Our work provides valuable pieces of experimental evidence for exploring the formation mechanism of natural diamonds.