Effect of Annealing Temperature on the Structural and Optical Properties of ZrO2 Thin Films

Davinder Kumar,Avtar Singh,Navneet Kaur,Apoorva Katoch,Raminder Kaur 한국재료학회 2022 한국재료학회지 Vol.32 No.5

Transparent thin films of pure and nickel-doped ZrO2 are grown successfully by sol-gel dip-coating technique. The structural and optical properties according to the different annealing temperatures (300 oC, 400 oC and 500 oC) are investigated. Analysis of crystallographic properties through X-ray diffraction pattern reveals an increase in crystallite size due to increase in crystallinity with temperature. All fabricated thin films are highly-oriented along (101) planes, which enhances the increase in nickel doping. Scanning electron microscopy and energy dispersive spectroscopy are employed to confirm the homogeneity in surface morphology as well as the doping configuration of films. The extinction coefficient is found to be on the order of 102, showing the surface smoothness of deposited thin films. UV-visible spectroscopy reveals a decrease in the optical band gap with the increase in annealing temperature due to the increase in crystallite size. The variation in Urbach energy and defect density with doping and the change in annealing temperature are also studied.

The study of hyperostosic variants: significance of hyperostotic variants of human skulls in anthropology

Jasbir Kaur,Dhirendra Srivastava,Davinder Singh,Shashi Raheja 대한해부학회 2012 Anatomy & Cell Biology Vol.45 No.4

Minor variations in the ossicles, foramina and ridges of the cranium have aroused the curiosity of anatomists for many decades. These non-metric variants help us to study the genetic relationships among ancient populations. Since these traits show considerable frequency differences in different populations, they can be used as anthropological characters in epidemiological studies. These variants indirectly reflect the part of underlying genotype of a given population thus implying their usefulness in biological comparisons of related groups. They can be used for the assessment of the existence of the parental structures within a community or as taxonomic indicators. For anthropological studies, the traits should be genetically determined, vary in frequency between different populations and should not show age, sex, and side dependency. The present study was conducted on hundred dry adult human skulls from Northern India. They were sexed and studied for the presence of hyperostotic traits (double hypoglossal canal, jugular foramen bridging, and paracondylar process). Sexual and side dimorphism was observed. None of the traits had shown statistically significant side and sexual dimorphism. Since the dimorphism is exhibited by none of them, it can be postulated that these traits are predominantly under genetic control and can be effectively used for population studies.

Relaxor characteristics of highly tunable lead-free 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 thin film grown on LaNiO3/Si by pulsed laser deposition

Chandan Bhardwaj,Davinder Kaur 한국물리학회 2012 Current Applied Physics Vol.12 No.5

We report a comprehensive study on relaxor-like characteristics exhibited by (l00) oriented 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 thin film grown on LaNiO3 coated Si substrate by pulsed laser deposition. The diffuseness coefficient value close to 2 and excellent fit of VogeleFulcher curve to the experimental data, suggest its relaxor characteristics. The ‘butterfly’ shaped dc field dependence of permittivity and evolution of PeE hysteresis loop, at different temperatures, clearly indicate the occurrence of polar nanoregions in this material. The high tunability nr ~ 70 and low temperature coefficient TCC = 5.18 × 10-4 K-1 show that the BCZT50 ceramics could be a promising candidate for tunable capacitor applications.

Exemestane encapsulated copolymers L121/F127/GL44 based mixed micelles: solubility enhancement and in vitro cytotoxicity evaluation using MCF-7 breast cancer cells

Singh Gurdeep,Singh Davinder,Choudhari Manisha,Kaur Simran Deep,Dubey Sunil Kumar,Arora Saroj,Bedi Neena 한국약제학회 2021 Journal of Pharmaceutical Investigation Vol.51 No.6

Purpose The present study aimed to develop a novel therapeutic approach for controlled delivery of exemestane (EXE) to cancer cells using nanostructured polymeric micelles. Methods A simplex centroid design of experiment study was employed for optimizing the polymeric micelle formulation to achieve the desired critical quality attributes, including micelle size, drug loading (DL), encapsulation efficiency (EE), and critical micelle concentration (CMC). The oil-in-water (o/w) solvent evaporation method was used to prepare mixed micelles (MMs) of copolymers L121/F127/GL44 for encapsulating EXE. Profile analysis tensiometer methods were used to determine the CMC of the copolymer mixture. EXE-MMs, blank mixed micelles, and lyophilized mixed micelles (Lyp- EXE-MMs) were characterized for other key quality attributes, such as zeta potential, chemical interactions, and morphology. Results The optimized ratio of L121/F127/GL44 was 1.98, 0.812, and 1.20, respectively, providing EXE-MMs with small micelle sizes (35.45 ± 1.20 nm), higher EE (89.75 ± 2.14%), and DL (5.85 ± 2.14%). EXE-encapsulated MMs exhibited an in vitro sustained release profile with improved cytotoxicity against MCF-7 cells than that with pure EXE. The cellular growth inhibitory concentration ( IC50) of EXE-MMs was 0.225 ± 0.124 μg/ml, while that of naïve EXE was 7.58 ± 0.145 μg/ ml. Moreover, in vivo pharmacokinetic parameters of EXE micellar formulation showed significant improvement in Cmax and AUC (0–72 h), viz. 207.54 ± 18.65 ng/ml and 3530.77 ± 212.25 ng h/ml, respectively, suggesting enhanced bioavailability than that of pure EXE. Conclusion EXE-MMs have a great potential for enhancing the bioavailability of EXE.

Electric field involved transport at elevated temperature in nanocrystalline silicon carbide nitride (nc-SiCN) thin films for harsh environment applications

Narendra Singh,Kirandeep Singh,Davinder Kaur 한국물리학회 2018 Current Applied Physics Vol.18 No.2

The present study represents a systematic temperature dependent charge transport and dielectric properties of nanocrystalline silicon carbide nitride (nc-SiCN) thin films grown on Pt/Ti/SiO2/Si substrate. A large negative temperature coefficient of resistance (TCR) ranging from 6200 to 2300 ppmK-1 in the temperature range 300e773 K, suggests that the nc-SiCN thin films could be useful for futuristic thermal-based sensors. The current density vs. electric field (J-E) characteristics was measured at different temperatures (300e673 K). Detailed J-E analysis revealed an ohmic conduction at the low applied electric field (<65 kV/cm) within the entire temperature range. However, at high electric field (>65 kV/cm), space charge limited conduction (SCLC) mechanism was found to be dominating in low measurement temperature (300e473K), whereas, a transition from SCLC mechanism to Poole-Frenkel mechanism was observed with further increment in the temperature beyond 473 K. The temperature invariant dielectric tunability (nr ~10%) and low zero electric field leakage current density (J ~107A/cm2) at 673 K temperature, demonstrates the feasibility of nc-SiCN thin films for tunable device applications in the high-temperature and harsh environment.

Fabrication of Densely Distributed Silver Indium Selenide Nanorods by Using Ag+ Ion Irradiation

Dinesh Pathak,R. K. Bedi,Davinder Kaur,Ravi Kumar 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.57 No.3

We prepared polycrystalline silver indium selenide thin films by vacuum evaporation on Si (100) substrates at a high temperature using a stochiometric powder. The films were characterized by X-ray diffraction (XRD) and UV-VIS-NIR spectroscopy. For the fabrication of densely distributed one-dimensional nanostructures of silver indium selenide on Si substrates, thermally evaporated films of AIS on Si (100) substrates were irradiated by incident 200-MeV Ag+ ions at a fluence of 5 × 1011 ion/cm2. At elevated substrate temperatures, silver indium selenide (AIS) exhibited a nanorod -like structure. The optical and the structural properties of the irradiated films were studied using UV-VIS-NIR Reflection spectroscopy, atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM), and XRD. The controlled fabrication of such densely distributed onedimensional nanorods on a Si substrate by using the ion beam technique, we believe, will open a variety of applications, such as nanoelectronics and optoelectronics devices.

Enhanced exchange bias in magnetron-sputtered NieMneSbeAl ferromagnetic shape memory alloy thin films

Rahul Barman,Sushil Kumar Singh,Davinder Kaur 한국물리학회 2014 Current Applied Physics Vol.14 No.12

In the present study, the influence of aluminium (Al) addition on the martensite-austenite phase transformation and exchange bias of NieMneSb films have been investigated. NieMneSbeAl films with different Al concentration (~0e5.6%) were deposited by co-sputtering of NieMneSb and Al targets. Experimental results revealed the decrease in martensitic transformation temperature with increasing Al content upto a certain extent (3.3%) beyond which martensitic transformation was suppressed. Paramagnetic to ferromagnetic transition temperature (TC) also decreased with increasing Al concentration. Ni50Mn36.3Sb10.4Al3.3 thin film showed significant improvement in exchange bias field as compared to pure Ni50.3Mn36.9Sb12.8 thin film. This enhancement in the exchange bias field HEB ¼ 611 Oe at 10 K is attributed to the increase of AFM-FM interactions that result from the decrease of MneMn distance due to the incorporation of Al atoms. This behaviour is an additional property of the FSMA thin films apart from various other multifunctional properties and therefore, is of technological importance for their applications in magnetic storage devices. ©

Effect of AlN layer on the resistive switching properties of TiO2 based ReRAM memory devices

Bhawani Pratap Singh Rathore,Ravi Prakash,Davinder Kaur 한국물리학회 2018 Current Applied Physics Vol.18 No.1

The present study reports the resistive switching behaviour in Titanium Dioxide (TiO2) material, with possible implementations in non volatile memory device. The Cu/TiO2/Pt memory device exhibit uniform and stable bipolar resistive switching behaviour. The current-voltage (I-V) analysis shows two discrete resistance states, the High Resistance State (HRS) and the Low Resistance State (LRS). The effect of an additional AlN layer in the resistive memory cell is also investigated. The Cu/TiO2/AlN/Pt device shows a multilevel (tri-state) resistive switching. Multilevel switching is facilitated by ionic and metallic filament formation, and the nature of the formed filaments is confirmed by performing a resistance vs. temperature measurement. The bilayer device shows improved reliability over the single layer device. The formation of high thermal conductive interfacial oxy-nitride (AlON) layer is the main reasons for the enhancement of resistive switching properties in Cu/TiO2/AlN/Pt cell. The performance of device was measured in terms of endurance and retention, which exhibits good endurance over 105 cycles and long retention time of 105 s at 125 C. The above result suggests the feasibility of Cu/TiO2/AlN/Pt devices for multilevel non volatile ReRAM application.

Improved resistive switching performance in Cu-cation migrated MoS2 based ReRAM device incorporated with tungsten nitride bottom electrode

Ravi Prakash,Shubham Sharma,Anuj Kumar,Davinder Kaur 한국물리학회 2019 Current Applied Physics Vol.19 No.3

The resistive switching characteristics of sputtered deposited molybdenum disulphide (MoS2) thin film has been investigated in Cu/MoS2/W2N stack configuration for Resistive Random Access Memory (ReRAM) application. The benefits of incorporating tungsten nitride (W2N) as a bottom electrode material were demonstrate by stability in operating voltages, good endurance (103 cycles) and long non-volatile retention (103 s) characteristics. Resistive switching properties in Cu/MoS2/W2N structure are induced by the formation/disruption of Cu conducting filaments in MoS2 thin film. Ohmic law and space charge limited current (SCLC) are observed as dominant conduction mechanism in low resistance state (LRS) and high resistance state (HRS) respectively. This study suggests the application of MoS2 thin films with W2N bottom electrode for next generation non-volatile ReRAM application.

Effect of Substrate Temperature on the Structural, Optical, and Electrical Properties of Silver-indium-selenide Films Prepared by Using Laser Ablation

Dinesh Pathak,R. K. Bedi,Davinder Kaur 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.56 No.3

KrF pulse UV excimer laser ablation of films of AgInSe2 (AIS) onto the glass substrates kept at different temperature using a ultra-high-vacuum deposition system has been studied. The AIS target was synthesized from high-purity materials. The compositional stoichiometry was observed to be largely maintained in the films. This suggests that Pulse Laser Deposition can be used as technique for fabrication of ternary semi conducting films. The X-ray diffraction studies of the films show that the films are textured in the (112) direction. The c/a ratio of 1.93, which is indicative of distortion, confirms its tetragonally-distorted chalcopyrite structure. The structural, optical and electrical properties have been investigated as functions of the substrate temperature. An increase in substrate temperature results in a more ordered structure. Field emission scanning electron microscopy (FESEM) observations show more compactness and densely packed arrangements with increasing substrate temperature. The roughness of the film is found to increase at higher deposition temperatures. The optical studies of the films show that the optical band gap lies in the range 1.20- 1.27 eV. The activation energy is in the range 0.0103 - 0.0556 eV.