Trap Depth Parameters Research Articles

Optical behavior, TL defect center analysis and photocatalytic characterization of Ag2O doped ZnO nano crystals

The objective of the study is to prepare Ag+-dopedZnO nano crystals and to assess their structure, optical behavior, TL analysis, photocatalytic activity. Using sol–gel technique the Ag+-doped ZnO nano crystals prepared. Using the FT-IR, XRD, BET surface area, SEM, EDX characterization techniques, we have examined the structure of the developed samples. The TL analysis of samples was done under a dose of 25 kGy gamma irradiation. Trap depth parameters of the samples evaluated. Which suggested the ZnO nano crystals doped with Ag+ ions are purely TL active. The optical studies such optical absorption, photoluminescence of samples reveal their optical behavior. The optical band gap of the samples also evaluated. Which is increasing with increase in concentration of Ag+ ions in ZnO nano crystals. Using the MV (10 ppm) and CR (10 ppm) dyes, under visible light the photocatalytic activity of the samples reported. At a reaction period of 90 min, the nano powdercontaining 1.0 mol% Ag+-dopedZnO nano crystals and a band gap energy of 2.75 eV demonstrated the best photocatalyticefficiency (∼91 %) in both colors. The evaluationwas done on the impact of radical scavenger research and catalyst dosage on degrading efficiency. The rate of reaction in the presence of 1.0 mol% Ag+-dopedZnO nano crystals was four times higher than the ZnO catalyst's rate constants, and the degradation reaction follows pseudo-first-orderkinetics. The degrading process shows pseudo-first-order kinetics, and the reaction rate was four times higher than the ZnO catalyst in the presence of 1.0 mol% Ag+-dopedZnO nano crystals. It took three cycle runs for the degrading efficiency to drop by 1 %. Thus, 1.0 mol% Ag+-dopedZnO nano crystals was employed as a promising photocatalyst with strong reusability potential for the degradation of textile colors, which will be very beneficial.

Influence of Antimony doping on electrical and photoelectrical response in Indium Selenide crystals

Indium Selenide (InSe) is the most suitable photovoltaic conversion material with narrow band gap (1.3 eV) in the layered semiconductors. The optical and transport properties of InSe offer significant potential for promising applications in the modern era of electronics and photo-electronic devices. The aim is achieved by high electric conductivity of InSe crystals, SbxIn1−xSe (x= 0.00, 0.10, 0.15, 0.20) crystals was grown by direct vapour transport (DVT) technique. The chemical compositional and surface morphology properties of grown crystals were studied by energy dispersive X-ray analysis (EDAX) and scanning electron microscope (SEM) respectively. The hexagonal crystal structure of grown crystal has revealed by X-ray diffraction (XRD) spectra. The dopant concentration of antimony (Sb) was found to have a decreasing effect on the optical band gap and activation energy as calculated through absorption spectra and Arrhenius relations respectively. The photo-response parameters: growth-decay and trap-depth parameters have been obtained using growth-decay curve. These results confirm that SbxIn1−xSe crystal was collective applicant for electronic and optoelectronic devices.

A study of trap depth parameters and photo response parameters of tin diselenide (SnSe2) crystal

Tin diselenide (SnSe2) layered crystals have been grown by a direct vapor transport technique. SnSe2 is an anisotropic binary-layered material would see capable for highly potential applications. The stoichiometric proportion of constituent elements and structure of grown crystals have been accomplished by EDAX spectrum and powder X-ray diffraction analysis respectively. The X-ray diffraction practices of grown crystal revealed the type of structure and micro structural parameters of grown crystals. The Photo conducting responsivity (R*) = 21.7, 24.1, 24.9, 25.1 mA/W, specific detectivity (D) = 5.44 × 108, 6.05 × 108, 6.23 × 108, 6.30 × 108 jones and external quantum efficiency (EQE) = 4.087 %, 4.541 %, 4.678 %, 4.730 % are evaluated at illumination intensities 50 mW/cm2, 75 mW/cm2, 100 mW/cm2 and 125 mW/cm2 for photo-response characterization respectively. The trapdepth parameters of the SnSe2 crystals are explicated on the basis of defect controlled photoconductivity mechanism. The trap depth energies 550 meV, 551 meV, 542 meV and 538 meV are evaluated at illumination intensities 50 mW/cm2, 75 mW/cm2, 100 mW/cm2 and 125 mW/cm2 respectively. The investigational results confirm that the tin diselenide (SnSe2) layered crystals are accomplished for solar cell and photo-detection applications.

A study of photoelectric properties of grown SnSe2 crystal by direct vapour transport technique

The opto-electrical properties of Tin Diselenide (SnSe2) crystal are significant for application in photo detectors, optoelectronic devices and many more. Metal chalcogenide SnSe2 has been grown by direct vapor transport (DVT) technique. The chemical composition of grown crystal was studied by energy dispersive analysis of X-ray (EDAX). The photo detection property of SnSe2 crystal based photo detector was exploited for their envisioned applications in optoelectronics. SnSe2 crystals have observed an outstanding photo response ability at room temperature (300 K) with changing illumination intensities 50, 75, 100 and 125 mw/cm2. Moreover, the related parameters, photoresponsivity (R) spectral detectivity (D), external quantum efficiency (EQE), internal quantum efficiency (IQE) and trap depth parameters have been evaluated for pure SnSe2 crystal.

Structural, optical and luminescence properties of BaLaGa3O7: x Eu3+ ceramic phosphors

The undoped and Eu3+ doped BaLaGa3O7 ceramic phosphors have been prepared using solid state reaction technique. The structural studies have been done using X-ray Diffraction (XRD) and Fourier transform infra-red (FTIR) technique and the surface morphology analysis using Field emission scanning electron microscope (FESEM). The elemental analysis has been carried out using Energy Dispersive X-ray spectroscopy (EDX) and elemental mapping. XRD study reveals that all the prepared phosphors are single phase with tetragonal crystal structure. The FESEM and EDX spectra confirm the single phase nature of the phosphors. FTIR technique identifies the various vibrational modes present in the prepared phosphors. The UV–Visible analysis provides the absorption region and band gap energies of undoped as well as doped BaLaGa3O7 phosphors. The photoluminescence (PL) excitation spectra consist of sharp excitation peaks of Eu3+ ions at 374 and 394 nm. The emission spectra corresponding to excitation wavelengths of 374 and 394 nm have been carried out. Maximum PL emission is obtained for excitation at 374 nm and it provides excellent orange red emission. The decay profile of BaLaGa3O7:xEu3+ phosphors have been carried out. The mechanoluminescence (ML) property of the doped phosphors reveals good ML emission without any pre irradiation. The information about the trap depth parameters and charge carriers in the 1 kGy irradiated BaLaGa3O7 phosphor has been studied using the thermoluminescence (TL) glow curves. The BaLaGa3O7 phosphor is having kinetics of first order with activation energy 1.107 eV.

EPR-TL correlation, in radiation shielding Ba(10-x)MnxLa30Si60 glasses

The well-known phenomenon, electron paramagnetic resonance, and thermoluminescence are used to investigate paramagnetically, and thermo-luminescent behavior of the materials to advance magneto-thermo-lumina applications. However, still, there is a necessity to introduce a correlation (or) mechanism in between electron paramagnetic resonance, and thermoluminescence to understand the radiation shielding (or) electromagnetic induction shielding phenomenon within the resource like glasses, ceramics, thin film (or) polymers. In this view, the Ba(10-x)MnxLa30Si60 series of glasses are prepared. The non-crystallinity behavior and glass-forming abilities are verified by X-ray diffraction and differential thermal analysis characterization techniques. The glasses are showing non-homogeneity, de-polymerization, entropic, and de-clustering behavior with increased MnO concentration. The thermal stabilities of the glasses are reported from the DTA studies. Ultrasonic velocities were recorded to evaluate the elastic characteristics of glasses. The radiation shielding studies of glasses suggest the radiation shielding phenomenon purely a function of the MnO concentration. In this view, the results and values of mass attenuation coefficient, radiation protection efficiency, mean free path, and energy absorption build-up factor suggest more glassy thickness is required to attenuate high energy radiation. The electron paramagnetic resonance reports suggest high order of dipole-dipole super exchange interaction and rhombohedral distortion within the glasses. Which also reveals the six-state characteristic trace of the octahedral Mn2+ ions. Upon 50 kGy, γ-irradiation, the thermoluminescence properties of the glasses are reported. Trap depth parameters are calculated, which reveal the resource developed are thermoluminescent at low activation energies. Moreover, to introduce the detailed correlation between electron paramagnetic resonance, and thermoluminescence phenomenon, we have annealed the glasses under 0 to 300°C temperature and upon the 0 to 50 kGy γ - irradiation dose level. In this view, the results upon the electron paramagnetic resonance and thermoluminescence properties obtained for the glasses are highly correlative.

Structure, and opto-dielectric investigations of Cu2+ -doped calcium bismuth silicate glass ceramics

CuO inclusive silicate glasses are well known for various semiconductor applications. However, there is a lot of demand and necessity of high efficient opto-dielectric materials. In view of this, the glasses of chemical composition (30 – x) CaO + (10) Bi2O3 + (60) SiO2 + (x) CuO have been synthesized and studied for their structural, optical and dielectric characterization techniques. Glassy behaviour of CuO undoped glass and ceramic behaviour of all other CuO doped glasses conformed by structural characterization. The elastic modulus and micro hardness of glass and glass ceramics reveal their inter connected covalent structure. Trap depth parameters (Tm, Eτ, Eδ, Eω & μs) have been determined and analysed under irradiation, and found that 0.3 mol% CuO -doped glass ceramic under 30 kGy of irradiation dose exhibiting better TL output. Dielectric relaxation studies of the glass ceramics suggested that mixed conduction of both ionic and electronic. Observed dielectric results; dielectric constant (εr), dielectric loss (tanφ), temperature region of relaxation (ΔT), low activation energie's for conduction (Ea) and AC Conductivity (σac) suggesting that the glass ceramics are dielectric. Optical band gap (Eo), transition probability (At) and emission cross section (σ) corresponding to the emissive transition 3D1 → 1S0 assessed by optical techniques. All the results suggests that 0.3 mol% CuO -doped glass ceramic is a useful opto-dielectric resource.

Synthesis and characterization of direct vapour transport grown Sb2Se3 crystals

Antimony Selenide (Sb2Se3) crystals have been grown using Direct Vapour Transport (DVT) teechnique. The compositional, morphological, structural and photoconductive electrical properties of Sb2Se3 crystals have been characterized. SEM image shows that no defect was observed in Sb2Se3 crystal. XRD analysis revealed that the Sb2Se3 crystal has orthorhombic structure. The photoconductive parameters (Responsivity, Specific Detectivity, EQE and IQE) and Trap Depth parameters were determined by the growth-decay curve and they rely on illumination intensity of incident light. These characteristics of Sb2Se3 crystal portray it as one of the most favorable semi-conducting materials for efficient photo-electric devices.

The advancement of compelling Indium Selenide: synthesis, structural studies, optical properties and photoelectrical applications

Single crystals of Indium Selenide (InSe) were successfully grown by direct vapor transport method. The grown crystals were characterized by estimating their surface morphology, chemical composition, structural, optical and photoconductive properties using appropriate techniques. SEM image suggested that InSe crystal has layered-type surface without morphological defects. Also, the hexagonal structure of crystal has been confirmed by X-ray diffraction (XRD) spectra and selected area electron diffraction (SAED) pattern. The crystal exhibits high absorption coefficient (104 cm−1) in visible region and direct bandgap of 1.22 eV. The trap depth parameters and photoconductivity parameters were determined by the growth-decay curve and they depend upon illumination intensity, temperature and wavelength of incident light. The grown InSe crystals have excellent photoconductive properties and hence can be utilized in different photoelectrical applications.

Nd2O3 Influenced Al2O3 & Sb2O3 Functional PbO-SiO2 Glass Materials, 1.06 μm Photonic Resource

Silicates of neodymium oxide are well known for laser diode (or) white light emitting diode applications. However, there is a lot of need and necessity of high efficient laser (or) light emitting diodes. In such a way, the materials (10 – x) Al2O3 – (x) Sb2O3 – (0.1) Nd2O3 – (30) PbO – (59.9) SiO2 were synthesized, where the variable ‘x’ varies as 0, 2, 4, 6, 8 & 10 mol%. Dimensionally, arranged samples studied by structural, physical, elastic, thermoluminescent and optical characterization techniques. Analysis with regard to structure of present materials reveal that the glasses prepared were mechanical hard. Trap-depth parameters (Tm, μm, Eτ, Eδ & Eω) with regard to thermoluminiscence studies suggest, glasses prepared were thermally active for visible light. Judd – Ofelt theory well applied for optical studies. J-O Parameters (Ω2 , Ω4 and Ω6) found to be relatively better and maximum (~9.49, ~ 4.96 and ~ 4.58 × 10−20 cm2) for Al6Sb4 glass. Photoluminescence analysis, spectroscopic quality factor (~1.082), effective band width (Δλ ~ 41 nm), transition probability (At ~ 1499 s−1), stimulated emission cross section (σ ~ 1.29 × 10−20 cm2), branching ratio (β ~ 48%) and radiative life time (τrad ~ 195 μs) corresponding to the transition 4F3/2 → 4I9/2 of Nd3+ ions are suggesting Al6Sb4 glass is an useful 1.06 μm photonic resource.

Influence of Al3+ and Sb3+ ions on thermo and photoluminescence properties of Pr2O3 doped PbO – SiO2 glasses for optical use

The chemical composition of (SiO2)59.9 – (PbO)30 – (Pr2O3)0.1 – (Sb2O3)x: (Al2O3)y – x have chosen for present glass synthesis, where the variable ‘x’ varies from 0 to 10 mol% and againstly ‘y’ varies from 10 to 0 mol% with a step size of 2 mol%. The samples were characterized by structural, photo and thermoluminescence techniques. The evolutions of thermal stability, elastic modulus, micro hardness and glass transition quantities advised that they are mechanically hard in nature. The γ - irradiated trap-depth parameters such as A.E. (~0.371eV) and shape symmetry ratio (~0.236) related to the thermoluminiscence characterization advised that the sample code ‘PAS6’ is a useful TL asset. The Judd - Ofelt quantities are derived from optical absorption spectra such as Ω2, Ω4 and Ω6 are found to be best for the glass code ‘PAS6’ (~8.64, ~4.65 and ~3.88 × 10−20 cm2) is a useful optical resource. Radiative parameters derived from photoluminescence characterization such as spectroscopic quality factor (~1.198), effective bandwidth (Δλ ~ 32 nm), transition probability (At = 1271 s−1), stimulated emission cross section (σ = 1.321 × 10−20 cm2), branching ratio (β ~ 49%) and radiative life time (τrad = 217 μs) are advising that the sample code ‘PAS6’ is a useful luminescent resource for various optical applications.

Approaching new photo-electrics: CdTe nano-crystallite thin film

Cadmium telluride (CdTe) is immensely interesting narrow band gap semiconductor with high electrical conductivity having promising applications in new-generation electronics and photo-electronic devices. In the present study, CdTe thin film was fabricated by thermal evaporation technique onto pre-cleaned glass substrate. The EDAX result indicates that the prepared thin film has non-stoichiometric nature. The SEM image revealed that the film is continuous and free form defects. The optical band gap is about 1.53 eV evaluated using absorption spectra. Using photo-response characterization, the responsivity (R*), specific detectivity (D), internal quantum efficiency (IQE) and external quantum efficiency (EQE) are determined as a function of illumination intensity. The effect of cycle numbers and applied voltage on the growth and decay parameters such as dispersion parameters (α), characteristic temperature (To) and localized state distribution parameter (Eo) are determined. The trap depth parameters of CdTe thin film is explicated on the basis of defect controlled photoconductivity mechanism. These results confirm that the CdTe thin film is a capable contender for photo-detection applications.

Physical properties and thermoluminescence of glasses designed for radiation dosimetry measurements

Soda lime glasses doped with CeO2, Nd2O3 and MnO2 were prepared. Thermoluminescence (TL) properties, such as glow curves and linearity of TL response on irradiation dose were investigated. Results showed that the TL properties depended on the type and concentration of the dopants. Samples were selected to calculate energy trap depth parameters. To design materials for radiation dosimetry, physical properties, ion concentration, elastic properties and effective atomic numbers are important. Theoretical bond compression models were used to determine the elastic moduli for comparison with experimental values. Results show fair agreement between theoretical and experimental measurements. The high elastic moduli of the glass samples indicated high rigidity and stability of the glass matrix structure.

Infrared luminescence and thermoluminescence of lithium borate glasses doped with Sm3+ ions

Abstract Thermoluminescence (TL) characteristics of X-ray irradiated pure and doped with Sm3+ ions Li2O-MO-B2O3 (where MO=ZnO, CaO, CdO) glasses have been studied in the temperature range of 303 to 573 K. All the pure glasses exhibited single TL peaks at 382 K, 424 K and 466 K. When these glasses were doped with Sm3+ ions no additional peaks have been observed but the glow peak temperature of the existing glow peak shifted gradually towards higher temperatures with gain in intensity of TL light output. The area under the glow curve was found to be maximum for Sm3+ doped glasses mixed with cadmium oxide as a modifier. The trap depth parameters associated with the observed TL peaks have been evaluated using Chen’s formulae. The possible use of these glasses in radiation dosimetry has been described. The results clearly showed that samarium doped cadmium borate glass has a potential to be considered as a thermoluminescence dosimeter.

Influence of Nd3+ ions on TL characteristics of Li2O-MO-B2O3 (MO = ZnO, CaO, CdO) glass system

Thermoluminescence (TL) characteristics of X-ray irradiated pure and doped with Nd3+ ions glasses have been studied in the temperature range 303–573 K; all the pure glasses have exhibited single TL peak at 382, 424 and 466 K, respectively. When these glasses are doped with Nd3+ ions no additional peaks are observed but the glow peak temperature of the existing glow peak shifted gradually towards higher temperatures with gain in intensity of TL light output. The area under the glow curve is found to be maximum for Nd3+-doped glasses mixed with cadmium oxide as modifier. The trap depth parameters associated with the observed TL peaks have been evaluated using Chen’s formulae. The possible use of these glasses in radiation dosimetry has been described. The result clearly showed that neodymium (Nd)-doped cadmium borate glass has a potential to be considered as the thermoluminescence dosimeter.

Thermoluminescence studies on alkali-silicate glass doped with dysprosium oxide for use in radiation dosimetry measurement

Alkali-silicate glass doped with dysprosium oxide was prepared and investigated. Recycled window glass (RWG) was substituted with pure SiO2 chemical as starting material. Physical properties of the glass samples such as density, molar volume and ion concentrations were determined. The thermoluminescence properties such as sensitivity and linearity of the glass samples were investigated. Trap depth parameters were studied using the glow curve shape method. Moreover, the optical absorption of the glass samples was studied with the transition mechanisms of Dy3+ ions.

Dosimetric and kinetic parameters of lithium cadmium borate glasses doped with rare earth ions

Thermoluminescence (TL) characteristics of X-ray irradiated pure and doped with four different rare earth ions (viz., Pr3+, Nd3+, Sm3+ and Eu3+) Li2O–Cdo–B2O3 glasses have been studied in the temperature range 303–573 K; the pure glass has exhibited single TL peak at 466 K. When this glass is doped with different rare earth ions no additional peaks are observed but the glow peak temperature of the existing glow peak shifted gradually towards higher temperatures with gain in intensity of TL light output. The area under the glow curve is found to be maximum for Eu3+ doped glasses. The trap depth parameters associated with the observed TL peaks have been evaluated using Chen's formulae. The possible use of these glasses in radiation dosimetry has been described. The result clearly showed that europium doped cadmium borate glass has a potential to be considered as the thermoluminescence dosimeter.

Effect of Silver Concentration on Thermoluminescence Studies of (Cd0.95Zn.05)S Phosphors with Trap Depth Parameters Synthesized by Solid State Reaction Method

The present paper reports the synthesis and characterization of Ag+ doped (Cd0.95Zn.05)S phosphors. The effect of variable concentration of silver on thermoluminescence (TL) studies was investigated. The samples were prepared by solid state synthesis technique which is suitable for large scale production for phosphors. The starting materials used for sample preparation were CdS, ZnS, (Ag(NO3)3 and sodium chloride was used as a flux during synthesis. The prepared sample was characterized by X-ray diffraction technique (XRD). Sample shows hexagonal structure and the particle size calculated by Scherer’s formula. The prepared phosphors were also examined by thermoluminescence technique. For recording TL glow curve every time 2mg phosphor was irradiated by 254nm UV source and fixed the heating rate at 8 0 C s -1 . Sample shows wellresolved peak at 1020C for different concentration of Ag+. In addition, the effect of Ag+ concentration at fixed UV exposure time was studied. The effect of UV exposure time and dose versus intensity plot were studied. Sample shows linear response with dose and broaden peak with lower temperature shows the less stability and more fading in TL glow curve. Trapping parameters were calculated for every recorded glow curve. The heating rate effect on TL glow curve was also studied. The sample shows the shifting of TL glow curve towards to lower temperature side with increasing of heating rate. The kinetic parameters like trap depth, frequency factor were calculated by using the Peak shape method, which are discussed in details. The TL Glow curves were fitted in CGCD (computerized glow curve convolution deconvolution) technique & trapping parameters calculated.

Luminescence quenching by manganese ions in MO–CaF2–B2O3 glasses

Abstract Thermoluminescence (TL) characteristics of X-ray irradiated calcium fluoro borate glasses mixed with three different alkali oxide modifiers viz., Li2O, Na2O and K2O have been studied in the temperature range 303–600 K; all the glasses have exhibited single TL peak at 485, 541 and 497 K respectively. The glasses containing Na2O as modifier has exhibited the maximum TL light output. The doping of manganese oxide by a small concentration (0.2 mol%) in all these glasses has been observed to inhibit TL light output drastically with shifting of peak positions towards lower temperatures. The trap depth parameters associated with the observed TL peaks have been evaluated using Chen’s formulae. The probable mechanism responsible for quenching of TL emission by manganese ions in these glasses has been suggested with the aid of optical absorption, IR spectra and differential scanning calorimetric studies.