Kajal Jindal - Academia.edu (original) (raw)
Papers by Kajal Jindal
Materials Chemistry and Physics, 2021
In this work, the influence of incorporation of Cr in multiferroic BiFeO3 (BFO) using first princ... more In this work, the influence of incorporation of Cr in multiferroic BiFeO3 (BFO) using first principle calculations based on GGA + U approximation is investigated. The substitution of Cr is studied at Bi, Fe and O lattice sites and interstitial position in BiFeO3. The stability of the defects is studied via formation energy calculations for different charge states of various Cr related defects in BFO at realistic conditions (T, p O 2 ). From the analysis of the formation energy calculations derived for the different configurations, Cr is found to preferentially occupy the Fe site in BFO. Oxygen and bismuth vacancies play an important role in the conduction mechanisms. The migration energetics are studied for these vacancies in pure and doped BFO and the changes that occur in migration barriers upon Cr substitution are discussed.
Springer Proceedings in Materials
In this paper, the linear optical response of Cr doped BiFeO3 (BFCO) using first principles calcu... more In this paper, the linear optical response of Cr doped BiFeO3 (BFCO) using first principles calculations based on the density functional theory (DFT) is reported. The electronic and magnetic properties of BFCO are studied. Cr doping is found to result in an increase in magnetization in BFO. To corroborate the theoretical understanding in BFCO, Cr doped BFO thin film is also deposited via a multistep spin coating technique. The structural and optical characterization of the thin film are performed and the obtained results are compared with the theory.
Journal of Applied Physics
BiFeO3 (BFO) and BiFe1-xCrxO3 (BFCO) (x = 0, 0.01, 0.02, 0.03) thin films have been fabricated us... more BiFeO3 (BFO) and BiFe1-xCrxO3 (BFCO) (x = 0, 0.01, 0.02, 0.03) thin films have been fabricated using chemical solution deposition technique. The bandgap of BFO and BFCO thin films is found to be lying in the visible region making these films suitable candidates for potential solar energy harvesting applications. Density functional theory based calculations have also been performed to study the effect of B-site (Cr) doping on the electronic properties of BFO and BFCO. The BiFe1-xCrxO3 (x = 0.02) thin films exhibited well saturated PE hysteresis loops with a maximum remanent and saturation polarization of about 43 μC/cm2 and 64 μC/cm2, respectively. In contrast to pure BFO, a high value of short circuit current density (Jsc) of magnitude 766.60 μA/cm2 along with the open circuit voltage (Voc) of 106 mV was obtained for BiFe0.98Cr0.02O3 thin film structure under illumination with a laser of wavelength 470 nm and intensity 20 mW/cm2. The Au/BiFe0.98Cr0.02O3/ITO/glass heterostructure displays a remarkably enhanced value of Ion/Ioff ratio (8.4 × 104). The observed results clearly highlight the potential of Cr doped BFO thin film structure for the development of cost effective light-driven devices.
Journal of Electronic Materials
Innovative material configurations obtained by incorporating two-dimensional (2D) layers of MoS2 ... more Innovative material configurations obtained by incorporating two-dimensional (2D) layers of MoS2 (a two-dimensional material) with Fe doped ZnO (Fe:ZnO) thin films are found to exhibit high thermoelectric properties at lower temperature. The low dimensionality of material (MoS2) is expected to enhance the thermoelectric power factor because of the strong confinement of charge carriers. MoS2 layers have been incorporated in the Fe:ZnO thin film by depositing MoS2 layers over Fe:ZnO thin film and by fabricating the multilayered structure of MoS2 layers with Fe:ZnO. The fabricated structures were characterized for their structural, optical and morphological properties using the available characterization tools. The multilayer configuration of the MoS2 and Fe:ZnO (FZnMFZn) sample was found to exhibit higher values of power factor of 1.06 × 10−3 W/mK2 and figure of merit (ZT) of 3.11 × 10−2 at a very low operating temperature of 300 K. The obtained results highlight the importance of charge confinement in improving the thermoelectric properties of the multilayered structure (FZnMFZn thin film sample) indicating that it is a promising candidate for practical applications.
Materials Today: Proceedings
Physica Scripta
The effect of unintentional doping by a light element like hydrogen atom in an important multifer... more The effect of unintentional doping by a light element like hydrogen atom in an important multiferroic perovskite oxide, BiFeO3 has been reported. Hydrogen is the lightest element and ubiquitous in the environment and thus is quite likely to get incorporated in material during fabrication stages. Unintentional dopant like H in a material may result in modification of the electronic properties. Formation energy calculations predict that H 1+ impurity is more stable in BFO grown under oxygen-rich conditions, whereas, H1− is only stable in BFO with n-type doping. H 1− is observed to induce doubly ionizable isolated occupied states, whereas, in the case of neutral H atom these states are singly occupied. Based on first principle calculations, H atom is observed to induce isolated impurity states within the forbidden gap which acts as compensating centers for acceptor and donor type impurities.
Materials Today: Proceedings
Materials Chemistry and Physics
Abstract An electrochemical sensor is fabricated using indium tin oxide (ITO) electrode loaded wi... more Abstract An electrochemical sensor is fabricated using indium tin oxide (ITO) electrode loaded with 3-Amino-1,2,4-triazole-5-thiol functionalized multiwall carbon nanotubes (T-MWCNTs) for detection of thallium. The modified MWCNTs were characterized by FTIR spectroscopy, SEM and HRTEM studies. SEM images demonstrated that the width of tubular structure of T-MWCNTs increase considerably after functionalization. The electrochemical response of the prepared sensor is analysed by performing differential pulse anodic stripping voltammetry (DPASV). T-MWCNTs based sensor was found to exhibit good sensitivity and a broad linear range of 10 - 100 μg L-1 along with a limit of detection (LOD) of 1.29 μg L-1 for Tl(I). The sensor showed good repeatability (RSD of 1.16 % and 2.09 % for 20 and 50 μg L-1 concentrations of Tl(I) respectively) and retained ∼95% of its response even after 15 days, indicating high stability of T-MWCNTs/ITO/glass electrode towards the detection of thallium. The applicability of the prepared sensor was analysed in real industrial water samples with the help of spiking study that was performed using certified Tl(I) solution traceable to National Institute of Standards and Technology (NIST) and demonstrated a recovery > 96%.
Advanced Science, Engineering and Medicine
Physical Chemistry Chemical Physics
The electronic structure and properties of carbon incorporated BiFeO3, and resolution to the cond... more The electronic structure and properties of carbon incorporated BiFeO3, and resolution to the conductivity aspects of BiFeO3.
Spin polarized calculations are performed to study the structural and electronic properties of Mn... more Spin polarized calculations are performed to study the structural and electronic properties of Mn doped BiFeO3 (BMFO) using simplified local spin density approximation (LSDA) functional under density functional theory (DFT). The B-site doping concentration of Mn in BMFO considered to be 16.7 % (BiMn0.167Fe0.833O3). Density of states calculations are carried out for both ferromagnetic (FM) and anti-ferromagnetic (AFM) order in BMFO. The results predict that BMFO is a half metal for both FM and AFM BMFO with magnetization of 29.0000 µB/cell and 1.0000 µB/cell respectively. The ground state of BMFO is found to be antiferromagnetic and demonstrates BMFO to be a potential candidate for spintronic applications.
Dyes and Pigments
Abstract A Pyrene appended bis-triazolylated-1,4-dihydropyridine based fluorescent probe L1 was s... more Abstract A Pyrene appended bis-triazolylated-1,4-dihydropyridine based fluorescent probe L1 was synthesized using Cu(I)-catalyzed click chemistry approach. Among the various metal ions tested, L1 showed selective binding towards Cu2+. L1 formed a 1:1 ligand-metal complex with an association constant, Ka = 6.63 × 104 M−1 as revealed by Job's plot and Benesi-Hildebrand plot, respectively. The detection limit of L1 for Cu2+ was found out to be 0.53 μM. The fluorescence response of L1 and L1-Cu2+ with varying pH was determined which showed that L1 works well, over a broad pH range. The binding mechanism of L1 with Cu2+ was well explored by density functional theory studies. Further, the probe was found to be non toxic under experimental conditions in various cancerous and normal cell lines. Fluorescence microscopy showed that L1 was cell permeable and could be served as a fluorescent probe for the detection of the presence and absence of Cu2+analytes in human primary glioblastoma cells (U-87). Also, paper strips of L1 were tested in aqueous media to set up a cost effective method for detection of Cu2+ ions.
Integrated Ferroelectrics
Abstract In the present work, the electronic and magnetic properties of Li doped BiFeO3 (BFO:Li) ... more Abstract In the present work, the electronic and magnetic properties of Li doped BiFeO3 (BFO:Li) are calculated using density functional theory (DFT). The exchange and correlation part of the energy functional is implemented through LSDA + U functional, where U is the Hubbard parameter which considers the localization of Fe d electrons. The obtained results suggest that Li doping induces weak ferromagnetism in BFO. The value of magnetic moment per unit volume of Li doped BFO is calculated to be 0.9992 /cell. The value of bandgap of Li doped BFO (1.921 eV) is found to reduce considerably in comparison to pure BFO (2.24 eV). The decrease in the value of bandgap in BFO upon Li doping may be attributed to the appearance of electronic states in the forbidden region with respect to pure BFO.
Journal of Magnetism and Magnetic Materials
Abstract Non-collinear antiferromagnetic (AFM) spin structure is imposed in Bi2Fe4O9 to study the... more Abstract Non-collinear antiferromagnetic (AFM) spin structure is imposed in Bi2Fe4O9 to study the electronic and magnetic properties of magnetically ordered Bi2Fe4O9 using first principles. Electronic properties carried out for both ferromagnetic (FM) and antiferromagnetic (AFM) orderings in Bi2Fe4O9 suggest that FM Bi2Fe4O9 is a semiconductor with an indirect optical bandgap of 1.732 eV, whereas, AFM Bi2Fe4O9 is a multiband semiconductor. The influence of different magnetic orderings on the electronic properties of Bi2Fe4O9 are studied in detail. The linear optical response of FM Bi2Fe4O9 is also investigated.
Sensors and Actuators B: Chemical
Abstract An array of p–n junction heterostructures is fabricated by loading the surface of n-type... more Abstract An array of p–n junction heterostructures is fabricated by loading the surface of n-type semiconducting ZnO thin film with p-type CuO microclusters (μCs) for realization of uric acid biosensor without any external mediator. Uricase is immobilized onto the prepared CuO/ZnO arrayed heterostructure in order to prepare the sensing electrode. The electrochemical performance of the prepared p - n junction based biosensor is investigated by means of cyclic voltammetry. A stable and well-defined peak corresponding to oxidation of uric acid is observed at a very low potential of 0.03 V in a mediator free solution. The largely decreased sensing potential may be attributed to the substantial enhancement of surface reaction kinetics in the formed p - n junction heterostructure due to built-in electric field which facilitate charge transport. A linear sensing response is observed over a range of 0.05–1.0 mM uric acid concentration with a high sensitivity of 1.74 mA/mM. Moreover, the prepared biosensor has good affinity towards uric acid (K m ∼ 0.05 mM) and possesses long shelf life ( >20 weeks). The low operating potential (0.03 V) of CuO/ZnO arrayed p - n heterojunction reduces the energy consumption of developed biosensor and efficiently minimizes interference from common oxidizable interferents, thereby, making the biosensor highly selective. Thus, CuO μCs/ZnO thin film based p - n junction heterostructure with internal electric field is a novel matrix for developing low powered biosensors to meet future energy demands.
Journal of Applied Physics, 2016
N doped ZnO (ZnO:N) thin films are prepared by pulsed laser deposition in an oxygen environment u... more N doped ZnO (ZnO:N) thin films are prepared by pulsed laser deposition in an oxygen environment using ZnO:N targets with varying nitrogen doping concentrations (1%–10%). The impact of nitrogen incorporation on the microstructural properties of prepared ZnO:N thin films has been studied using Raman scattering. The Raman shift of E2(high) mode towards lower frequencies indicate the substitution of N at O lattice sites (NO). A local vibrational mode corresponding to Zn–N was observed at 480.3 cm−1 in N doped ZnO thin films and highlights the increased strength of the Zn–N bond in the ZnO lattice. Photoluminescence studies reveal the dominant near band edge emission peak in the ultraviolet region and the absence of deep level emission due to defects. The ZnO:N thin films are found to possess room temperature ferromagnetism. N is found to play a significant role in arising ferromagnetism in ZnO and possess a solubility limit of 8% for uniform and homogeneous atomic substitution in ZnO. The present study confir...
Applied Physics A, 2015
In this paper, we propose three divide-and-conquer approaches for BIC-based speaker segmentation.... more In this paper, we propose three divide-and-conquer approaches for BIC-based speaker segmentation. The approaches detect speaker changes by recursively partitioning a large analysis window into two sub-windows and recursively verifying the merging of two adjacent audio segments using ∆BIC, a widelyadopted distance measure of two audio segments. We compare our approaches to three popular distance-based approaches, namely, Chen and Gopalakrishnan's window-growing-based approach, Siegler et al.'s fixed-size sliding window approach, and Delacourt and Wellekens's DISTBIC approach, by performing computational cost analysis and conducting speaker change detection experiments on two broadcast news data sets. The results show that the proposed approaches are more efficient and achieve higher segmentation accuracy than the compared distance-based approaches. In addition, we apply the segmentation approaches discussed in this paper to the speaker diarization task. The experiment results show that a more effective segmentation approach leads to better diarization accuracy.
Integrated Ferroelectrics, 2014
ABSTRACT First principle calculations were performed to study room temperature ferromagnetism in ... more ABSTRACT First principle calculations were performed to study room temperature ferromagnetism in N doped ZnO (ZnO:N) using spin density functional theory. Substitution of O by N in ZnO results in spin polarized state exhibiting half metallic ferromagnetic characteristics. Each N dopant introduces magnetic moment of 1.0 μB/supercell, which is from 2p electrons of N but the magnetization energy (ΔE = 14.42 meV) is too small to stabilize ferromagnetism at room temperature. Cobalt (Co) co-doping in ZnO:N is found to enhance ferromagnetism (magnetic moment = 4.24 μB/supercell) with enhanced stability (ΔE = 635 meV) and is driven by hybridization between N 2p and Co 3d states.
Materials Chemistry and Physics, 2021
In this work, the influence of incorporation of Cr in multiferroic BiFeO3 (BFO) using first princ... more In this work, the influence of incorporation of Cr in multiferroic BiFeO3 (BFO) using first principle calculations based on GGA + U approximation is investigated. The substitution of Cr is studied at Bi, Fe and O lattice sites and interstitial position in BiFeO3. The stability of the defects is studied via formation energy calculations for different charge states of various Cr related defects in BFO at realistic conditions (T, p O 2 ). From the analysis of the formation energy calculations derived for the different configurations, Cr is found to preferentially occupy the Fe site in BFO. Oxygen and bismuth vacancies play an important role in the conduction mechanisms. The migration energetics are studied for these vacancies in pure and doped BFO and the changes that occur in migration barriers upon Cr substitution are discussed.
Springer Proceedings in Materials
In this paper, the linear optical response of Cr doped BiFeO3 (BFCO) using first principles calcu... more In this paper, the linear optical response of Cr doped BiFeO3 (BFCO) using first principles calculations based on the density functional theory (DFT) is reported. The electronic and magnetic properties of BFCO are studied. Cr doping is found to result in an increase in magnetization in BFO. To corroborate the theoretical understanding in BFCO, Cr doped BFO thin film is also deposited via a multistep spin coating technique. The structural and optical characterization of the thin film are performed and the obtained results are compared with the theory.
Journal of Applied Physics
BiFeO3 (BFO) and BiFe1-xCrxO3 (BFCO) (x = 0, 0.01, 0.02, 0.03) thin films have been fabricated us... more BiFeO3 (BFO) and BiFe1-xCrxO3 (BFCO) (x = 0, 0.01, 0.02, 0.03) thin films have been fabricated using chemical solution deposition technique. The bandgap of BFO and BFCO thin films is found to be lying in the visible region making these films suitable candidates for potential solar energy harvesting applications. Density functional theory based calculations have also been performed to study the effect of B-site (Cr) doping on the electronic properties of BFO and BFCO. The BiFe1-xCrxO3 (x = 0.02) thin films exhibited well saturated PE hysteresis loops with a maximum remanent and saturation polarization of about 43 μC/cm2 and 64 μC/cm2, respectively. In contrast to pure BFO, a high value of short circuit current density (Jsc) of magnitude 766.60 μA/cm2 along with the open circuit voltage (Voc) of 106 mV was obtained for BiFe0.98Cr0.02O3 thin film structure under illumination with a laser of wavelength 470 nm and intensity 20 mW/cm2. The Au/BiFe0.98Cr0.02O3/ITO/glass heterostructure displays a remarkably enhanced value of Ion/Ioff ratio (8.4 × 104). The observed results clearly highlight the potential of Cr doped BFO thin film structure for the development of cost effective light-driven devices.
Journal of Electronic Materials
Innovative material configurations obtained by incorporating two-dimensional (2D) layers of MoS2 ... more Innovative material configurations obtained by incorporating two-dimensional (2D) layers of MoS2 (a two-dimensional material) with Fe doped ZnO (Fe:ZnO) thin films are found to exhibit high thermoelectric properties at lower temperature. The low dimensionality of material (MoS2) is expected to enhance the thermoelectric power factor because of the strong confinement of charge carriers. MoS2 layers have been incorporated in the Fe:ZnO thin film by depositing MoS2 layers over Fe:ZnO thin film and by fabricating the multilayered structure of MoS2 layers with Fe:ZnO. The fabricated structures were characterized for their structural, optical and morphological properties using the available characterization tools. The multilayer configuration of the MoS2 and Fe:ZnO (FZnMFZn) sample was found to exhibit higher values of power factor of 1.06 × 10−3 W/mK2 and figure of merit (ZT) of 3.11 × 10−2 at a very low operating temperature of 300 K. The obtained results highlight the importance of charge confinement in improving the thermoelectric properties of the multilayered structure (FZnMFZn thin film sample) indicating that it is a promising candidate for practical applications.
Materials Today: Proceedings
Physica Scripta
The effect of unintentional doping by a light element like hydrogen atom in an important multifer... more The effect of unintentional doping by a light element like hydrogen atom in an important multiferroic perovskite oxide, BiFeO3 has been reported. Hydrogen is the lightest element and ubiquitous in the environment and thus is quite likely to get incorporated in material during fabrication stages. Unintentional dopant like H in a material may result in modification of the electronic properties. Formation energy calculations predict that H 1+ impurity is more stable in BFO grown under oxygen-rich conditions, whereas, H1− is only stable in BFO with n-type doping. H 1− is observed to induce doubly ionizable isolated occupied states, whereas, in the case of neutral H atom these states are singly occupied. Based on first principle calculations, H atom is observed to induce isolated impurity states within the forbidden gap which acts as compensating centers for acceptor and donor type impurities.
Materials Today: Proceedings
Materials Chemistry and Physics
Abstract An electrochemical sensor is fabricated using indium tin oxide (ITO) electrode loaded wi... more Abstract An electrochemical sensor is fabricated using indium tin oxide (ITO) electrode loaded with 3-Amino-1,2,4-triazole-5-thiol functionalized multiwall carbon nanotubes (T-MWCNTs) for detection of thallium. The modified MWCNTs were characterized by FTIR spectroscopy, SEM and HRTEM studies. SEM images demonstrated that the width of tubular structure of T-MWCNTs increase considerably after functionalization. The electrochemical response of the prepared sensor is analysed by performing differential pulse anodic stripping voltammetry (DPASV). T-MWCNTs based sensor was found to exhibit good sensitivity and a broad linear range of 10 - 100 μg L-1 along with a limit of detection (LOD) of 1.29 μg L-1 for Tl(I). The sensor showed good repeatability (RSD of 1.16 % and 2.09 % for 20 and 50 μg L-1 concentrations of Tl(I) respectively) and retained ∼95% of its response even after 15 days, indicating high stability of T-MWCNTs/ITO/glass electrode towards the detection of thallium. The applicability of the prepared sensor was analysed in real industrial water samples with the help of spiking study that was performed using certified Tl(I) solution traceable to National Institute of Standards and Technology (NIST) and demonstrated a recovery > 96%.
Advanced Science, Engineering and Medicine
Physical Chemistry Chemical Physics
The electronic structure and properties of carbon incorporated BiFeO3, and resolution to the cond... more The electronic structure and properties of carbon incorporated BiFeO3, and resolution to the conductivity aspects of BiFeO3.
Spin polarized calculations are performed to study the structural and electronic properties of Mn... more Spin polarized calculations are performed to study the structural and electronic properties of Mn doped BiFeO3 (BMFO) using simplified local spin density approximation (LSDA) functional under density functional theory (DFT). The B-site doping concentration of Mn in BMFO considered to be 16.7 % (BiMn0.167Fe0.833O3). Density of states calculations are carried out for both ferromagnetic (FM) and anti-ferromagnetic (AFM) order in BMFO. The results predict that BMFO is a half metal for both FM and AFM BMFO with magnetization of 29.0000 µB/cell and 1.0000 µB/cell respectively. The ground state of BMFO is found to be antiferromagnetic and demonstrates BMFO to be a potential candidate for spintronic applications.
Dyes and Pigments
Abstract A Pyrene appended bis-triazolylated-1,4-dihydropyridine based fluorescent probe L1 was s... more Abstract A Pyrene appended bis-triazolylated-1,4-dihydropyridine based fluorescent probe L1 was synthesized using Cu(I)-catalyzed click chemistry approach. Among the various metal ions tested, L1 showed selective binding towards Cu2+. L1 formed a 1:1 ligand-metal complex with an association constant, Ka = 6.63 × 104 M−1 as revealed by Job's plot and Benesi-Hildebrand plot, respectively. The detection limit of L1 for Cu2+ was found out to be 0.53 μM. The fluorescence response of L1 and L1-Cu2+ with varying pH was determined which showed that L1 works well, over a broad pH range. The binding mechanism of L1 with Cu2+ was well explored by density functional theory studies. Further, the probe was found to be non toxic under experimental conditions in various cancerous and normal cell lines. Fluorescence microscopy showed that L1 was cell permeable and could be served as a fluorescent probe for the detection of the presence and absence of Cu2+analytes in human primary glioblastoma cells (U-87). Also, paper strips of L1 were tested in aqueous media to set up a cost effective method for detection of Cu2+ ions.
Integrated Ferroelectrics
Abstract In the present work, the electronic and magnetic properties of Li doped BiFeO3 (BFO:Li) ... more Abstract In the present work, the electronic and magnetic properties of Li doped BiFeO3 (BFO:Li) are calculated using density functional theory (DFT). The exchange and correlation part of the energy functional is implemented through LSDA + U functional, where U is the Hubbard parameter which considers the localization of Fe d electrons. The obtained results suggest that Li doping induces weak ferromagnetism in BFO. The value of magnetic moment per unit volume of Li doped BFO is calculated to be 0.9992 /cell. The value of bandgap of Li doped BFO (1.921 eV) is found to reduce considerably in comparison to pure BFO (2.24 eV). The decrease in the value of bandgap in BFO upon Li doping may be attributed to the appearance of electronic states in the forbidden region with respect to pure BFO.
Journal of Magnetism and Magnetic Materials
Abstract Non-collinear antiferromagnetic (AFM) spin structure is imposed in Bi2Fe4O9 to study the... more Abstract Non-collinear antiferromagnetic (AFM) spin structure is imposed in Bi2Fe4O9 to study the electronic and magnetic properties of magnetically ordered Bi2Fe4O9 using first principles. Electronic properties carried out for both ferromagnetic (FM) and antiferromagnetic (AFM) orderings in Bi2Fe4O9 suggest that FM Bi2Fe4O9 is a semiconductor with an indirect optical bandgap of 1.732 eV, whereas, AFM Bi2Fe4O9 is a multiband semiconductor. The influence of different magnetic orderings on the electronic properties of Bi2Fe4O9 are studied in detail. The linear optical response of FM Bi2Fe4O9 is also investigated.
Sensors and Actuators B: Chemical
Abstract An array of p–n junction heterostructures is fabricated by loading the surface of n-type... more Abstract An array of p–n junction heterostructures is fabricated by loading the surface of n-type semiconducting ZnO thin film with p-type CuO microclusters (μCs) for realization of uric acid biosensor without any external mediator. Uricase is immobilized onto the prepared CuO/ZnO arrayed heterostructure in order to prepare the sensing electrode. The electrochemical performance of the prepared p - n junction based biosensor is investigated by means of cyclic voltammetry. A stable and well-defined peak corresponding to oxidation of uric acid is observed at a very low potential of 0.03 V in a mediator free solution. The largely decreased sensing potential may be attributed to the substantial enhancement of surface reaction kinetics in the formed p - n junction heterostructure due to built-in electric field which facilitate charge transport. A linear sensing response is observed over a range of 0.05–1.0 mM uric acid concentration with a high sensitivity of 1.74 mA/mM. Moreover, the prepared biosensor has good affinity towards uric acid (K m ∼ 0.05 mM) and possesses long shelf life ( >20 weeks). The low operating potential (0.03 V) of CuO/ZnO arrayed p - n heterojunction reduces the energy consumption of developed biosensor and efficiently minimizes interference from common oxidizable interferents, thereby, making the biosensor highly selective. Thus, CuO μCs/ZnO thin film based p - n junction heterostructure with internal electric field is a novel matrix for developing low powered biosensors to meet future energy demands.
Journal of Applied Physics, 2016
N doped ZnO (ZnO:N) thin films are prepared by pulsed laser deposition in an oxygen environment u... more N doped ZnO (ZnO:N) thin films are prepared by pulsed laser deposition in an oxygen environment using ZnO:N targets with varying nitrogen doping concentrations (1%–10%). The impact of nitrogen incorporation on the microstructural properties of prepared ZnO:N thin films has been studied using Raman scattering. The Raman shift of E2(high) mode towards lower frequencies indicate the substitution of N at O lattice sites (NO). A local vibrational mode corresponding to Zn–N was observed at 480.3 cm−1 in N doped ZnO thin films and highlights the increased strength of the Zn–N bond in the ZnO lattice. Photoluminescence studies reveal the dominant near band edge emission peak in the ultraviolet region and the absence of deep level emission due to defects. The ZnO:N thin films are found to possess room temperature ferromagnetism. N is found to play a significant role in arising ferromagnetism in ZnO and possess a solubility limit of 8% for uniform and homogeneous atomic substitution in ZnO. The present study confir...
Applied Physics A, 2015
In this paper, we propose three divide-and-conquer approaches for BIC-based speaker segmentation.... more In this paper, we propose three divide-and-conquer approaches for BIC-based speaker segmentation. The approaches detect speaker changes by recursively partitioning a large analysis window into two sub-windows and recursively verifying the merging of two adjacent audio segments using ∆BIC, a widelyadopted distance measure of two audio segments. We compare our approaches to three popular distance-based approaches, namely, Chen and Gopalakrishnan's window-growing-based approach, Siegler et al.'s fixed-size sliding window approach, and Delacourt and Wellekens's DISTBIC approach, by performing computational cost analysis and conducting speaker change detection experiments on two broadcast news data sets. The results show that the proposed approaches are more efficient and achieve higher segmentation accuracy than the compared distance-based approaches. In addition, we apply the segmentation approaches discussed in this paper to the speaker diarization task. The experiment results show that a more effective segmentation approach leads to better diarization accuracy.
Integrated Ferroelectrics, 2014
ABSTRACT First principle calculations were performed to study room temperature ferromagnetism in ... more ABSTRACT First principle calculations were performed to study room temperature ferromagnetism in N doped ZnO (ZnO:N) using spin density functional theory. Substitution of O by N in ZnO results in spin polarized state exhibiting half metallic ferromagnetic characteristics. Each N dopant introduces magnetic moment of 1.0 μB/supercell, which is from 2p electrons of N but the magnetization energy (ΔE = 14.42 meV) is too small to stabilize ferromagnetism at room temperature. Cobalt (Co) co-doping in ZnO:N is found to enhance ferromagnetism (magnetic moment = 4.24 μB/supercell) with enhanced stability (ΔE = 635 meV) and is driven by hybridization between N 2p and Co 3d states.