Y. Batra

Inter University Accelerator Centre, New Dilli, NCT, India

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Publications (12)14.67 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Formation of Ge crystallites in GeOx matrix as a result of heavy ion irradiation is reported. Micro-Raman spectra of the films show the evolution of Ge crystallite regions in GeOx thin films upon ion irradiation with 100 MeV Au. Transmission electron microscopic studies of the irradiated films revealed the presence of Ge crystallites. Crystallinity of the Ge nanoparticles was confirmed by high-resolution electron microscope images. Atomic force microscopy was employed to study the modifications in surface morphology of GeOx films before and after irradiation. Formation of Ge nanocrystallites has been explained on the basis of phenomenon of ion beam induced phase separation.
    Surface & Coatings Technology - SURF COAT TECH. 01/2009; 203(17):2415-2417.
  • Y. Batra, D. Kanjilal
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    ABSTRACT: Formation of controlled semiconductor nanostructures on and near the surface region using dense electronic excitation produced by high energy heavy ions has been reviewed. Various parameters of the energetic ion beams such as energy, species and beam current can be controlled to have desired size. Results of new initiatives on production of Ge nanostructures of desired size by high-energy heavy ions are discussed. GeO<sub align="right">x</sub> films were irradiated by 100 MeV gold (Au) ions. Formation of Ge nanostructures was studied by various techniques like micro Raman, Fourier transform infrared spectroscopy (FTIR), glancing incident X-ray diffraction (GIXRD), transmission electron microscopy (TEM), high resolution electron microscopy (HREM), atomic force microscopy (AFM), elastic recoil detection analysis (ERDA), magnetic force microscopy (MFM) and magnetisation measurements. Development of Ge nanostructures is explained on the basis of phase separation of GeO<sub align="right">x</sub> and controlled crystallisation of Ge in the nanometre scale taking place around the trajectory of the swift heavy ion. Nanostructures are formed in a controlled manner by dense electronic excitation due to melting and subsequent fast cooling of the region along the trajectories of the energetic ions.
    International Journal of Nanotechnology - INT J NANOTECHNOL. 01/2009; 6.
  • Y Batra, D Kabiraj, D Kanjilal
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    ABSTRACT: Germanium (Ge) nanoparticles have attracted a lot of attention due to their excellent optical properties. In this paper, we report on the formation of Ge nanoparticles embedded in GeO2 matrix prepared by electron beam evaporation and subsequent annealing. Transmission electron microscopy (TEM) studies clearly indicate the formation of Ge nanocrystals in the films annealed at 500 degrees C. Fourier transform infrared (FTIR) spectroscopic studies are carried out to verify the evolution of the structure after annealing at each stage. Micro-Raman analysis also confirms the formation of Ge nanoparticles in the annealed films. Development of Ge nanoparticles is also established by photoluminescence (PL) analysis. Surface morphology study is carried out by atomic force microscopy (AFM). It shows the evolution of granular structure of the films with increasing annealing temperature.
    Journal of Nanoscience and Nanotechnology 09/2008; 8(8):4081-5. · 1.15 Impact Factor
  • Y. Batra, T. Mohanty, D. Kanjilal
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    ABSTRACT: Ion beams at varied energies have been used as versatile and powerful technique for synthesizing nanophases of materials on and near the surface region of a variety of host matrices. An overview of recent developments regarding fabrication of semiconductor nanoparticles using energetic ion beams is presented. Results of new initiatives on the production of group IV (Si and Ge) nanostructures of desired size by high-energy heavy ions are discussed. Controlled crystallization in the nanometer scale takes place around the trajectory of the swift heavy ion passing through the host matrix. Nanoparticles with specific phases can be formed in a controlled manner by dense electronic excitation due to melting and subsequent fast cooling of the region along the trajectories of the ion beams.
    Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms. 01/2008;
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    ABSTRACT: The electrical characteristics of Au/n-Si (1 0 0) Schottky rectifier have been studied in a wide irradiation fluence range using conventional current-voltage (I-V) and capacitance-voltage (C-V) measurements. The I-V characteristics showed an abnormal increase in forward current at low voltage. The device shows a bend in forward I-V and reverses bias C-V characteristics due to extra current, suggesting that there are two independent contributions to thermionic current, corresponding to two levels of the Schottky barrier. It is shown that the excess current at low voltage can be explained by taking into account the role of heavy ion irradiation induced defects at the metal semiconductor interface. (c) 2007 Elsevier B. V. All rights reserved.
    Applied Surface Science 01/2008; 254(11):3277-3281. · 2.54 Impact Factor
  • Y. Batra, D. Kabiraj, D. Kanjilal
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    ABSTRACT: The effect of crystallinity of Ge nanocrystals on the charge storage properties of the metal oxide semiconductor (MOS) structure has been investigated. MOS structure with Ge nanocrystals embedded in the oxide has been fabricated by using atom beam sputtering technique. After annealing at 600°C in Ar+H2 atmosphere, capacitance–voltage (C–V) measurements show flat band voltage shift of ∼0.9V. It which is a clear indication of the memory effect of Ge nanocrystals, while unannealed structure doesnot show any hysteresis in the C–V curve. Micro Raman spectroscopy and X-ray diffraction (XRD) analyses show that crystalline content of Ge nanoparticles in the MOS structure has increased after annealing.
    Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms 01/2008; 266(1):63-66. · 1.27 Impact Factor
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    ABSTRACT: Elastic recoil detection (ERD) analysis of GeOx thin films was carried out to understand the mechanism of phase separation. Stoichiometry of the film was monitored on-line at various fluences of 100MeV Au ions. Although significant electronic sputtering of GeOx film was observed but the stoichiometry remained almost constant up to a fluence of 3×1012ions/cm2. Structural modifications of the films after irradiation was studied by offline glancing angle X-ray diffraction (GAXRD), which showed the presence of Ge crystallites in the films. The results indicate that the phase separation does not occur because of preferential sputtering of oxygen but may occur as a result of rearrangement of Ge and O atoms within the films. The activation for rearrangement is provided by ion impact.
    Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms 01/2008; 266(8):1697-1700. · 1.27 Impact Factor
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    ABSTRACT: The influence of swift heavy (180 MeV 107Ag14+) ion irradiation on Au/n-Si Schottky diode characteristics has been analysed using in situ current–voltage (I–V) characterization. The values of the Schottky barrier height (SBH), the ideality factor and series resistance Rs for each irradiation fluence have been obtained from the forward bias I–V characteristics. For an unirradiated diode, the SBH and ideality factor were 0.74 ± 0.01 eV and 1.71, respectively. The barrier height decreases to 0.69 ± 0.01 eV as the fluence increases to a value of 1 × 1011 ions cm−2. It is found that after an irradiation fluence of 1 × 1011 ions cm−2 the SBH remains immune to further irradiation up to a fluence of 5 × 1012 ions cm−2. The observed behaviour is interpreted on the basis of energy loss mechanisms of energetic ions at the metal–semiconductor interface and irradiation-induced defects.
    Journal of Physics D Applied Physics 11/2007; 40(22):6892. · 2.53 Impact Factor
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    ABSTRACT: Irradiation of thin films of sub stoichiometric germanium oxide (GeOx) has been carried out using swift heavy ions. Micro-Raman studies of the films indicate the formation of Ge crystallites as a result of irradiation. Moreover, crystallinity of Ge improves with an increase in fluence. Glancing angle x-ray diffraction results also confirm the presence of Ge crystallites in the irradiated samples. Fourier transformed infrared spectroscopy was employed to study the Ge–O–Ge vibrational structure before and after irradiation. Formation of Ge crystallites has been explained on the basis of the phenomenon of ion-beam-induced phase separation.
    Journal of Physics D Applied Physics 07/2007; 40(15):4568. · 2.53 Impact Factor
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    ABSTRACT: Nanocrystalline tin oxide (SnO2) thin films grown by RF magnetron sputtering technique were characterized by UV-Visible absorption spectroscopy and Photoluminescence spectroscopy. From atomic force microscopic (AFM) and Glancing angle X-ray diffraction (GAXRD) measurements, the radius of grains was found to be approximately 6+/-2 nm. The thin films were bombarded with 250 keV Xe2+ ion beam to observe the stability of nanophases against radiation. For ion bombarded films, optical absorption band edge is shifted towards red region. Atomic force microscopy studies show that the radius of the grains was increased to approximately 8 +/- 1 nm and the grains were nearly uniform in size. The size of the grains has been reduced after ion bombardment in the case of films grown on Si. During this process, defects such as vacancies, voids were generated in the films as well as in the substrates. Ion bombardment induces local temperature increase of thin films causing melting of films. Ion beam induced defects enhances the diffusion of atoms leading to uniformity in size of grains. The role of matrix on ion beam induced grain growth is discussed.
    Journal of Nanoscience and Nanotechnology 07/2007; 7(6):2036-40. · 1.15 Impact Factor
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    ABSTRACT: Charge retention properties of Ge nanoparticles embedded in SiO$_{2}$ matrix are investigated. Formation of embedded Ge nanoparticles was accomplished by optimizing electron beam evaporation process. Size of Ge nanoparticles has been characterized by atomic force microscopy (AFM) which comes out to be ~15 nm. Presence of Ge nanoparticles is confirmed by micro-Raman analysis. Memory effect of Ge nanoparticles is verified by capacitance-voltage ($C$-$V$) measurements which show hysteresis in the $C$-$V$ curves.
    The European Physical Journal Applied Physics 01/2007; · 0.71 Impact Factor
  • Y. Batra, D. Kabiraj, D. Kanjilal
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    ABSTRACT: Germanium (Ge) nanocrystals (NCs) have attracted a lot of attention due to their excellent optical properties. In this paper we report on the formation of Ge nanoparticles embedded in GeO2 matrix by electron beam evaporation and subsequent annealing. Charge retention properties of Ge NCs thus synthesized are also investigated. Fourier transform infrared (FTIR) spectroscopic studies are carried out to verify the evolution of the NCs. Micro-Raman analysis also confirms the formation of Ge nanoparticles in the annealed films. Development of Ge nanoparticles is established by photoluminescence (PL) analysis. The memory effect of Ge NCs is revealed by the hysteresis in the capacitance–voltage (C–V) curves of the fabricated metal-oxide-semiconductor (MOS) structure containing Ge NCs.
    Solid State Communications 01/2007; · 1.53 Impact Factor

Publication Stats

21 Citations
14.67 Total Impact Points

Institutions

  • 2007–2009
    • Inter University Accelerator Centre
      • Materials Science Group
      New Dilli, NCT, India
    • Jawaharlal Nehru University
      • School of Physical Sciences
      New Delhi, NCT, India
  • 2008
    • University of Allahabad
      • Department of Physics
      Allahābād, Uttar Pradesh, India