BITS Faculty Publications

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Subject: search.filters.subject.Amorphous materials

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    Sub-0.18 /spl mu/m SOI MOSFETs using lateral asymmetric channel profile and Ge pre-amorphization salicide technology
    (IEEE, 1998-10) Rao, V. Ramgopal
    SOI devices are of great interest, especially for low power and low voltage applications. To achieve this goal, the device threshold voltage must be lowered while maintaining low sub-threshold leakage. However, when devices are downscaled, short channel effects (SCE) and hot carrier effects (HCE) also become severe issues in SOI MOSFETs. Symmetric halo implantations are widely used in bulk MOSFETs to improve SCE. Recently, asymmetric channel implantation or "pocket implantation" on the source end was introduced in bulk MOSFETs to adjust the threshold voltage and improve the device SCE and HCE. In this work, for the first time, we introduce large tilt angle implantation in the SOI MOSFET to form a lateral asymmetric channel (LAC) doping profile after gate formation. High concentration channel doping near the source end reduces DIBL and threshold voltage roll-off while low doping concentration near the drain side ensures high mobility. Furthermore, the peak electric field near the drain is reduced and impact ionization is less serious compared to conventional devices.
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    Effect of Substrates on the Photoelectrochemical Reduction of Water over Cathodically Electrodeposited p-Type Cu2O Thin Films
    (ACS, 2015-08-05) Pande, Surojit
    In this study, we demonstrate development of p-Cu2O thin films through cathodic electrodeposition technique at constant current of 0.1 mA/cm2 on Cu, Al, and indium tin oxide (ITO) substrates from basic CuSO4 solution containing Triton X-100 as the surfactant at 30–35 °C. The optical and morphological characterizations of the semiconductors have been carried out using UV–vis spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and Raman spectroscopy. The band gap energy of ∼2.1 eV is recorded, whereas SEM reveals that the surface morphology is covered with Cu2O semiconductors. XRD analyses confirm that with change in substrate, the size of Cu2O “cubic” crystallites decreases from ITO to Al to Cu substrates. Photoelectrochemical characterizations under dark and illuminated conditions have been carried out through linear sweep voltammetry, chronoamperometry and electrochemical impedance spectroscopic analysis. The photoelectrochemical reduction of water (H2O → H2) in pH 4.9 aqueous solutions over the different substrates vary in the order of Cu > Al > ITO. The highest current of 4.6 mA/cm2 has been recorded over the Cu substrate even at a low illumination of 35 mW/cm2, which is significantly higher than the values (2.4 mA/cm2 on Au coated FTO or 4.07 mA/cm2 on Cu foil substrate at an illumination of 100 mW/cm2) reported in literature.
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    Magnetic resonance lineshapes in powdered and amorphous systems
    (IAS, 1986-04) Sivasubramanian, S.C.
    A survey is made of the theory and applications ofEPR andNMR absorption lineshapes observed in powdered and amorphous materials. The ‘spin Hamiltonian’ and ‘resonance condition’ formalisms are reviewed, andepr andnmr lineshapes are discussed which typify the singularity characteristics in powdered materials. In the amorphous or ‘glassy’ state, the measurable spin resonance parameters often have to be viewed as being ‘randomly distributed’ according to a probability density function. Several recent probability-theory based approaches to lineshape computation for modelling the amorphous state are discussed.