Thulium Oxide Research Articles

Structural, chemical, and metal-oxide-semiconductor characteristics of RF magnetron sputtered thulium oxide passivation layer on 4H-silicon carbide substrate

Thulium oxide (Tm2O3) passivation layer (PL) deposited on 4H-silicon carbide (SiC) that was subjected to postdeposition annealing at 700 °C in forming gas-oxygen-forming gas ambient was reported for the first time in this work. X-ray photoelectron spectroscopy characterization revealed the success of annealing process in minimizing the concentration of oxygen vacancies and also curbed the presence of TmO suboxide bonding in the annealed Tm2O3 PL. In addition, XPS characterization has also disclosed the incorporation of nitrogen ions into the Tm2O3 lattice through the annealing process in which grazing incidence X-ray diffraction has also revealed the shift of detected peaks with regards to Tm2O3 phases to small diffraction angles. Although X-ray reflectivity measurements have disclosed the formation of thicker SiO2 interfacial layer (IL) for the annealed Tm2O3 PL, the acquisition of a higher dielectric constant (k) by the annealed PL when compared to as-deposited PL has suggested that the formation of SiO2 IL has minimal effect toward the k value of annealed PL. Metal-oxide-semiconductor characteristics of the annealed Tm2O3 PL on 4H-SiC was systematically reported in this letter.

Cancer-Thylakoid Hybrid Membrane Camouflaged Thulium Oxide Nanoparticles with Oxygen Self-Supply Capability for Tumor-Homing Phototherapy.

Nanomaterials that generate reactive oxygen species (ROS) upon light irradiation have significant applications in various fields, including photodynamic therapy (PDT) that is widely recognized as a highly momentous strategy for the eradication of cancer cells. However, the ROS production rate of photosensitizers, as well as the tumor hypoxia environment, are two major challenges that restrict the widespread application of PDT. In this study, a cancer-thylakoid hybrid membrane-camouflaged thulium oxide nanoparticles (Tm2O3) for tumor-homing phototherapy through dual-stage-light-guided ROS generation and oxygen self-supply is developed. Tm2O3 as a type II photosensitizer are viable for NIR-stimulated ROS generation due to the unique energy levels, large absorption cross section, and long lifetime of the 3H4 state of Tm ions. The thylakoid membrane (TK) plays a catalase-like role in converting hydrogen peroxide into oxygen and also acts as a natural photosensitizer that can generate lethal ROS through electron transfer when exposed to light. In addition, fluorescence dye DiR is embedded in the hybrid membrane for in vivo tracing as well as photothermal therapy. Results show that tumors in Tm2O3@TK-M/DiR group are effectively ablated following dual-stage-light irradiation, highlighting the promising potential of rare-earth element-based type II photosensitizers in various applications.

Theoretical Ionizing Radiation Shielding Parameters of Thulium Doped Zinc Borotellurite Glass

Ionizing radiation is considered hazardous to human health but it is very crucial for many applications such as nuclear fuel processing and medical radiography. Glass has played a huge role as a shielding material for ionizing radiation in the application that requires line of sight. Nowadays, lead glass is commonly used in industry due to its properties of high density. However, lead toxicity can give harmful effects on humans’ health and the environment. As for concrete, it takes a lot of space, blocks the line of sight and the density of concrete may reduce due to prolonged exposure to radiation. To cater these problems, this study proposed a glass composition that is thulium doped zinc borotellurite glass. Thulium is used due to its potential such as resistance to corrosion and oxidation, good ductility and does not pose any environmental threat. In this study, Phy-X and WinXCom software is used. The main goal of this research is to study the theoretical radiation shielding parameters of thulium doped zinc borotellurite glass. Based on the results, it is found that the best glass sample is the sample composition with 5% thulium oxide whereby it has the highest value for mass attenuation coefficient (MAC), linear attenuation coefficient (LAC), atomic cross section (ACS), electronic cross section (ECS) and effective atomic number (Zeff). The best glass sample with 5% thulium oxide also yields the results of the lowest half-value layer (HVL) and mean free path (MFP). Comparing the results of Phy-X and WinXCom, it is found that the deviation between the software is less than 5%. Also, when the results for each radiation shielding parameter of 5% thulium oxide are compared with other radiation shielding materials, significant results are found where the proposed glass sample provides better shielding against gamma radiation.

Effects of post-deposition annealing in argon-oxygen-argon ambient on physical and electrical characteristics of thulium oxide passivation layer on silicon substrate

Effects of post-deposition annealing in argon-oxygen-argon ambient on physical and electrical characteristics of thulium oxide passivation layer on silicon substrate

Pressure driven polymorphic transitions in nanocrystalline Lu2O3, Tm2O3 and Eu2O3

The crystallite size of the materials considerably influences the material properties, including their compressibility and resistance to external forces and the stability of the crystalline structure; a corresponding study for which, so far, has been limited for the important class of nanocrystalline Rare Earth Sesquioxides (REOs). In the present study, we report the crystallographic structural transitions in nanocrystalline Rare Earth Oxides (REOs) under the influence of pressure, investigated via high-energy X-Ray Diffraction (XRD) measurements. The study has been carried out on three of the REOs, namely Lutetium oxide (Lu2O3), Thulium oxide (Tm2O3) and Europium oxide (Eu2O3) up to the pressures of 33, 22 and 11 GPa, respectively. The diffraction data of Lu2O3 and Tm2O3 suggests the occurrence of irreversible structural transitions from cubic to monoclinic phase, while Eu2O3 showed a transition from the cubic to hexagonal phase. The transitions were found to be accompanied by a collapse in the volume and the resulting Pressure–Volume (P–V) graphs are fitted with the 3rd order Birch-Murnaghan (BM) equation of state (EOS) to estimate the bulk moduli and their pressure derivatives. Our study establishes a qualitative relationship between the crystallite size and various material properties such as the lattice parameters, transition pressure, bulk modulus etc., and strengthens the knowledge regarding the behaviour of this technologically important class of materials.

Efficient Tm3+ up-conversion in lead borophosphate glasses for visible emission

Thulium oxide (Tm2O3) doped lithium lead borophosphate glasses have been synthesised and analysed to probe their structural and luminescence properties. X-ray diffraction data confirmed the non-crystalline nature of the prepared glasses. Participation of Tm2O3 in the structure is established by the variation in density and molar volume with increasing concentration of Tm2O3. Fourier transform infrared spectroscopy revealed the various structural units present due to B2O3, P2O5 and PbO. Ultraviolet-visible near infrared absorption spectra showed peaks/bands at 466 nm (G41), 684 nm (F33), 790 nm (H43) and 1210 nm (H53), originating from ground state H63 of thulium while Ytterbium showed its characteristic peak at 978 nm. Indirect band gap, calculated from Tauc's curve showed decreasing trend with increasing concentration of Tm2O3. The other optical parameters like molar refractivity, molar polarizability, electronic polarizability and dielectric constant also showed variation with increase in concentration of Tm2O3. Judd-Ofelt parameters followed Ω2>Ω4>Ω6 trend and oscillator strengths have also been evaluated. For luminescence studies, upon 790 nm excitation, visible peaks at 454 nm, 485 nm, 529 nm, 624 nm and 665 nm were observed while at 684 nm excitation, wavelength of 542 nm and 610 nm is emitted. Excited state absorption up-conversion mechanism is responsible for the observed visible emission. Commission Internationale de I'Eclairage (CIE) chromaticity coordinates have also been calculated and coordinates lie near the white light region. Up-conversion results indicated that the prepared glasses are potential host for up-conversion and can be used in colour displays.

Solution-processed rare-earth thulium oxide with high permittivity for low-voltage transistor and inverters applications

The use of high-permittivity (high-k) thin films as gate dielectrics is essential in the development of low-power electronics. In this work, rare-earth thulium oxide (Tm2O3) thin films were prepared by a facile solution process and annealed at various temperatures from 400 to 700 °C. The evolution of the physical and dielectric properties of Tm2O3 thin film with annealing temperature was investigated. It is demonstrated that the Tm2O3 thin film annealed at 600 °C exhibits the optimal performance, including a low leakage current of 3 × 10−10 A/cm2, a large areal capacitance of 250 nF/cm2 at 100 Hz, and a high permittivity value of 14.2. The Tm2O3 thin film as a gate insulator was integrated into the thin film transistor (TFT) employing In2O3-based semiconducting channels. The In2O3 TFT with 600 °C-annealed Tm2O3 dielectric exhibits the superior performance, with a high Ion/Ioff of 1.65 × 107, a small subthreshold swing (SS) value of 0.2 V/dec, a VTH of +1.8 V, and a mobility of 1.68 cm2/(V·s). Furthermore, an inverter constructed by connecting the TFT with a resistor exhibits full-swing characteristics. This work provides a facile and appealing method for preparing the high-k Tm2O3 thin films as alternative gate dielectrics with the potential for use in low-power electronics and logic circuit applications.

Oxygen–Ion Conductivity, Dielectric Properties and Spectroscopic Characterization of “Stuffed” Tm2(Ti2−xTmx)O7−x/2 (x = 0, 0.1, 0.18, 0.28, 0.74) Pyrochlores

Tm2(Ti2−xTmx)O7−x/2 (x = 0, 0.1, 0.18, 0.28, 0.74) solid electrolytes have been investigated as potential electrolyte materials for solid oxygen fuel cells (SOFCs), operating in the medium temperature range (600–700 °C). The design of new oxygen-conducting materials is of importance for their possible utilization in the solid oxide fuel cells. The oxygen–ion conductivity of the Tm2(Ti2−xTmx)O7−x/2 (x = 0, 0.1, 0.18, 0.28, 0.74) “stuffed” pyrochlores ceramics was investigated by electrochemical impedance spectroscopy (two-probe AC) in dry and wet air. The synthesis of precursors via co-precipitation and the precipitate decomposition temperature have been shown to be of key importance for obtaining dense and highly conductive ceramics. At ~770 °C, the highest total conductivity, ~3.16 × 10−3 S/cm, is offered by Tm2Ti2O7. The conductivity of the fluorite-like solid solution Tm2(Ti2−xTmx)O7−x/2 (x = 0.74) is an order of magnitude lower. However, for the first time a proton contribution of ~5 × 10−5 S/cm at 600 °C has been found in Tm2(Ti2−xTmx)O7−x/2 (x = 0.74) fluorite. Until now, compositions with proton conductivity were not known for the intermediate and heavy rare earth titanates Ln2(Ti2−xLnx)O7−x/2 (Ln = Ho − Lu) systems. The use of X-ray diffraction (structural analysis with Rietveld refinement), optical spectroscopy and dielectric permittivity data allowed us to follow structural disordering in the solid solution series with increasing thulium oxide content. High and low cooling rates have been shown to have different effects on the properties of the ceramics. Slow cooling initiates’ growth of fluorite nanodomains in a pyrochlore matrix. The fabrication of such nanostructured dense composites is a promising direction in the synthesis of highly conductive solid electrolytes for SOFCs. We assume that high-temperature firing of nanophase precursors helps to obtain lightly doped “stuffed” pyrochlores, which also provide the high oxygen–ion conductivity.

Structural, morphological, and metal-oxide-semiconductor characteristics of thulium oxide passivation layer grown in nitrogen-oxygen-nitrogen ambient

Poor crystallinity of the as-deposited thulium oxide (Tm2O3) passivation layer deposited via radio frequency magnetron sputtering was improved after post-deposition annealing in nitrogen‑oxygen‑nitrogen ambient at different temperatures (500, 600, 700, and 800 °C). The nitrogen ions were incorporated into all of the investigated Tm2O3 passivation layers, accompanied with the generation of oxygen vacancies (Vo). The effects of nitrogen introduction on structural, morphological, and metal-oxide-semiconductor characteristics of Tm2O3 passivation layers were systematically investigated. Results indicated that the variation of the lattice parameter a (1.0447–1.0482 nm), band gap (direct band gap: 5.037–5.292 eV, indirect band gap: 4.059–5.063 eV), root-mean-square roughness (1.40–2.20 nm), dielectric constant, k (7.6–16.0), and the interface quality were evidenced to be closely related to the introduction of nitrogen, as well as the generation of Vo after post-deposition annealing at 600 and 700 °C, which would be partly annihilated at 800 °C. Furthermore, the presence of nitrogen near the interface could restrain the formation of interfacial layer. The highest k value (16.0) was obtained by the Tm2O3 passivation layer subjected to post-deposition annealing at 700 °C while the best interface quality was acquired at 800 °C shown by the acquisition of approximately 1011 cm−1 for the interface trap density. Detailed exploration of the corresponding variation arisen from post deposition annealing in nitrogen‑oxygen‑nitrogen ambient at different temperatures was studied and compared.

Effect of thulium oxide on structural, refractive index, and optical band gap of bismuth-boro-tellurite glass system

The bismuth-boro-tellurite glass has been chosen by various analysts from all around the world due to its advantages and ability the improvement of glass technologies. This paper aims to study the structural and optical properties of the bismuth-boro-tellurite glass system with different amounts of thulium oxide as a glass dopant. Four glass sample from chemical composition of [(B2O3)0.25 (TeO2)0.75]0.75 [(Bi2O3)0.25]1-x [Tm2O3]x (x = 0.000, 0.005, 0.010, and 0.015 mol%) were prepared by melt-quenching method with suitable melting and quenching temperature. The Ultraviolet-Visible Spectroscopy (UV-Vis) was used for recording their optical absorption spectra. These optical absorption spectra were used to determine the optical band gap energy, refractive index, and polarizability of all glass samples. While the structural changes are observed using X-ray diffractometer (XRD) and Fourier Transform Infrared Spectroscopy (FTIR).

Innovative approach of growing thulium oxide passivation layer in nitrogen/oxygen/nitrogen ambient

• Growth of polycrystalline Tm 2 O 3 in nitrogen/oxide/nitrogen ambient. • Incorporating nitrogen ions into Tm 2 O 3 lattice. • Narrowing of Tm 2 O 3 band gap due to the presence of nitrogen ions. • MOS characteristics of Tm 2 O 3 passivation layer was reported. • Interface quality of Tm 2 O 3 /Si was evaluated. Thulium oxide (Tm 2 O 3 ) passivation layer was grown on silicon substrate using nitrogen/oxygen/nitrogen (NON) ambient at 600 °C. The incorporation of nitrogen ions into Tm 2 O 3 lattice has contributed to the release of oxygen ions, leading to the formation of positively charged oxygen vacancies, which could be supported by the shift of grazing incidence X-ray diffraction peaks with regards to Tm 2 O 3 to larger diffraction angle as well as the acquisition of positive effective oxide charge. Interface quality of the investigated Tm 2 O 3 passivation layer was examined based on Terman’s, Hill-Coleman and high-low frequency methods.

Effect of thulium boro-tellurite glass system on radiation shielding parameters

This article reports the influence of thulium oxide on gamma shielding parameters of (B2O3)0.2-x (TeO2)0.5 (Bi2O3)0.3 (Tm2O3)x glass system. The mass attenuation coefficient has been obtained by the WinXCom program, whereas the effective atomic number and the electron density have been calculated from a comprehensive and consistent set of formulas. Appreciable variations have been observed for all parameters by varying the chemical composition of the glass and the gamma photon energy. The theoretical results have shown that the addition of the rare-earth oxide, Tm2O3 into the glass system as the dopant attenuates more gamma irradiation and improves the radiation shielding properties of the glass system. The interactions between the photons and the glass materials have been explained by the Photoelectric Effect, Compton Scattering and Pair Production.

Study of ionizing radiation attenuation of glass as: gamma rays shielding material

The primary application of radiation shielding is to safeguard against the harmful effects of radiation. This study investigated the addition of thulium oxide (Tm2O3) to a glass system with a composition of 75 TeO2–5 Li2O–10 ZnO– (10-x)Nb2O5. Multiple radiationshielding parameters, including linear and mass attenuation coefficients, half-value layers, mean free paths, atomic and electronic cross-sections, effective atomic numbers, and effective electron density, were evaluated. The study compared the half-value layer values of the new composite to those of well-known radiation-shielding materials, which include ordinary concrete and commercial glass. The addition of Tm2O3 to glass systems efficiently increases the atomic and electronic cross-sections. While all samples had the greatest linear and attenuation coefficients of 201.5–232.84 cm2 /g at 15 keV, the denser glass had the highest mass attenuation coefficient of 42.80 cm2 /g. The shielding effectiveness depends on the phases structure of TeO2 occurred in the prepared glasses.

Near-Infrared Light-Excited Reactive Oxygen Species Generation by Thulium Oxide Nanoparticles.

Exploring materials that can absorb near-infrared (NIR) light to produce reactive oxygen species (ROS) is necessary for many fields. Herein we show that thulium oxide nanoparticles are viable for NIR-stimulated ROS generation. This property may be related to the unique energy levels, large absorption cross section, low fluorescence emission, and ∼10-3 s lifetime of the 3H4 state of Tm ions. We further demonstrate the impact of these nanoparticles on photodynamic therapy (PDT), in which impressive tumor inhibition was recorded after exposure to either a broadband halogen lamp or an 808 nm laser. Our results may provide insight into the areas of photocatalysis, pollution treatment, and fine chemical synthesis.

Effects of ZrO2 concentration on properties of Tm2O3 transparent ceramics by vacuum sintering

Thulium oxide (Tm2O3) transparent ceramics with outstanding optical transparency were successfully prepared with various contents (0–4 at%) of zirconia (ZrO2) added as sintering additive using pressureless vacuum sintering at 1850 °C for 8 h. The effect of ZrO2 content on the changes of microstructure, transparency, Vickers hardness, fracture toughness, and thermal conductivity of Tm2O3 transparent ceramics were systematically investigated in this research. The experimental measurements showed that the in-line transmittance of 3 at% ZrO2-doped Tm2O3 transparent ceramics with the grain size of 6.7 μm was 76.3% at the wavelength of 880 nm and approximately 85% in the range of 2100–2500 nm. In addition, the Vickers hardness and fracture toughness were significantly improved from 7.8 ± 0.4 to 10.2 ± 0.2 GPa and 0.97 ± 0.06 to 1.32 ± 0.10 MPa m1/2, respectively, with content of ZrO2 increasing from 0 to 4 at%, while on the contrary the thermal performance was observed to decrease. This study showed that the in-line transmittance of Tm2O3 ceramics with favorably combined optical and mechanical properties could be achieved by the proper tailoring of ZrO2 content.

Characterization and Photocatalytic Activity of TmVO4 Prepared by Hydrothermal Method

Using thulium oxide, nitric acid, ammonium metavanadate and citric acid as main raw materials, TmVO4 was successfully prepared by hydrothermal method. TmVO4 samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), thermogravimetry differential scanning calorimetry (TG-DSC), and Fourier transform infrared spectroscopy (FT-IR). Taking methyl orange solution as simulated sewage, the effects of synthesis temperature and illumination time on the photocatalytic activity of TmVO4 were studied. The results show that pure tetragonal zircon TmVO4 samples can be obtained under hydrothermal conditions of 120 °C to 180 °C. The sample prepared at 140°Chas uniform grain size, and the average grain size is about 50 nm. Under ultraviolet light illumination for 30 min, the degradation rate of 10 mg/L methyl orange can reach more than 77% in the presence of TmVO4. The photocatalysis experiment indicated that TmVO4 has good photocatalytic degradation activity for methyl orange.

Radiation protection assessment of gamma photons in 64TeO2–10WO3–10Nb2O5– 15KF–1La2O3 glasses doped with Tm2O3 using photon-shielding and dosimetry software

Radiation-shielding applications are necessary to protect against deleterious effects of radiation. This study tested thulium oxide (Tm2O3) added to the glass-system composition 64TeO2–10WO3–10Nb2O5–15KF–1La2O3. Adding Tm2O3 increased sample density from 5.22 to 5.40 g/cm3 and measured at photon energy of 15 keV–15 MeV. Multiple radiationshielding parameters were evaluated and assessed using photon-shielding and dosimetry software, including linear and mass attenuation coefficients, half-value layers, mean free paths, atomic and electronic cross sections, effective atomic numbers, effective electron density, and exposure buildup factors. Half-value layer and mean free-path values were compared with those of well-known radiation-shielding materials, ie, conventional concrete and commercial glasses. Atomic and electronic cross-section values effectively increased with the addition of thulium oxide to the glass systems. While the highest linear and attenuation coefficients were 242–281 cm2 /g at 15 keV, the denser glass recorded the highest mass attenuation coefficients value of 52.17 cm2 /g across all samples. The highest effective atomic number and effective electron density were recorded for the denser glass, because it had the highest thulium oxide fraction and was more burdened by interaction with photon energy. Half-value layers and mean free paths showed similar behavior, and high-density materials achieved low values. At high energy, exposure buildup-factor values increased, while at low energy, values decreased.

Viscosity of the Sodium–Borate Melts Containing Mechanically Activated Samarium, Europium, Erbium, and Thulium Oxides

Viscosity of the Sodium–Borate Melts Containing Mechanically Activated Samarium, Europium, Erbium, and Thulium Oxides

Optical and structural characterization of Tm2O3, TmN, and TmOxNy thin films grown by direct-current reactive magnetron sputtering

This paper reports the fabrication and characterization of several thulium oxide and nitride thin films grown by reactive magnetron direct-current sputtering. Hysteresis curves of the Tm emission spectra of the sputtering plasma versus the flow of N2 or O2 around the Tm-metal target were monitored. Emission spectra of atomic transition lines in the region between 370 and 420 nm were identified to be of neutral thulium. The plasma emission was compared to the hysteresis curves generated by monitoring the sputter rate and target voltage. The nitride films' composition and optical properties were determined by X-Ray Diffraction, and optical transmission spectroscopy. The composition of the oxide films was determined by energy dispersive X-ray spectroscopy. The films are initially amorphous but crystallize after thermal treatment at 800°C. The optical bandgap values obtained using the Tauc method are consistent with what has been previously reported for both Tm2O3 and TmN prepared by other methods.

Thulium oxide nanoparticles as radioenhancers for the treatment of metastatic cutaneous squamous cell carcinoma

Metastases from cutaneous squamous cell carcinoma (cSCC) occur in 2%–5% of cases. Surgery is the standard treatment, often combined with adjuvant radiotherapy. Concurrent carboplatin treatment with post-operative radiotherapy may be prescribed, although it has not shown benefit in recent clinical trials in high-risk cSCC patients. The novel high-Z nanoparticle thulium (III) oxide has been shown to enhance radiation dose delivery to brain tumors by specific uptake of these nanoparticles into the cancerous tissue. As the dose-enhancement capacity of thulium oxide nanoparticles following radiotherapy against metastatic cSCC cells is unknown, its efficacy as a radiosensitizer was evaluated, with and without carboplatin. Novel and validated human patient-derived cell lines of metastatic cSCC were used. The sensitivity of the cells to radiation was investigated using short-term proliferation assays as well as clonogenic survival as the radiobiological endpoint. Briefly, cells were irradiated with 125 kVp orthovoltage x-rays (0–6 Gy) with and without thulium oxide nanoparticles (99.9% trace metals basis; 50 µg ml−1) or low dose carboplatin pre-sensitization. Cellular uptake of the nanoparticles was first confirmed by microscopy and found to have no impact on short-term cell survival for the cSCC cells, highlighting the biocompatibility of thulium oxide nanoparticles. Clonogenic cell survival assays confirmed radio-sensitization when exposed to thulium nanoparticles, with the cell sensitivity increasing by a factor of 1.24 (calculated at the 10% survival fraction) for the irradiated cSCC cells. The combination of carboplatin with thulium oxide nanoparticles with irradiation did not result in significant further reductions in survival compared to nanoparticles alone. This is the first study to provide in vitro data demonstrating the independent radiosensitization effect of high-Z nanoparticles against metastatic cSCC with or without carboplatin. Further preclinical investigations with radiotherapy plus high-Z nanoparticles for the management of metastatic cSCC are warranted.