Sathyaharish Jeedigunta

Fabrication and characterization of ZnO nanowire arrays with an investigation into electrochemical sensing capabilities

ZnO nanowire arrays were grown on a Si (100) substrate using the vapor-liquid-solid (VLS) method. ZnO nanowires were characterized by XRD, SEM, bright field TEM, and EDS. They were found to have a preferential orientation along the c-axis. The as-prepared sample was functionalized with glucose oxidase by physical adsorption. FTIR was taken before and after functionalization to verify the presence of the attached enzyme. Electrochemical measurements were performed on the nanowire array by differential pulse voltammetry in the range of -0.6 to 0.4 V. The nanoarray sensor displayed high sensitivity to glucose in the range of 1.0 × 10-4 to 1.0 × 10-2 mol L-1.

Structural and Electrical Properties of Nanocrystalline Diamond based Barium Strontium Titanate Varactors

Barium strontium titanate (BST) varactors fabricated on silicon substrates experience reliability and yield issues due to the defects induced in the interdiffusion of the layers in the bottom electrode stack. The structural and electrical properties of BST varactors fabricated on nanocrystalline diamond (NCD) films as the diffusion barrier layer are reported here. The structural properties and the quality of the interfaces were studied along with the electrical properties of the varactors. The varactors fabricated on NCD films displayed improved symmetry of capacitance-voltage (C-V) characteristics and 70% higher quality factor due to better interface stability with reduced bottom electrode losses.

Chapter 12 – Nanocrystalline Diamond for RF-MEMS Applications

This article presents thermally actuated nanocrystalline diamond bridges for microwave and high power RF applications. The growth process along with the seeding technique for generating the diamond films has been discussed. RF applications which include mechanical resonators and electrostatically actuated switches demonstrated by other researchers is presented. The diamond bridges are integrated in CPW and microstrip topologies to operate as a switch and tunable inductor. In addition to small signal measurements, high power measurements in the range of 24-47 dBm are performed for the switches integrated in the microstrip topology.

Structural-property relationship of nanocrystalline diamond films and its applications

The importance and interest of diamond synthesis is based on the unique properties that can be achieved using this material in several applications. Micro and nanocrystalline diamond (NCD) films were deposited by microwave plasma enhanced chemical vapour deposition (MPECVD). The structural properties were characterised by SEM, TEM, Raman spectroscopy and NEXAFS. Nitrogen incorporated NCD films were grown to produce electrically conductive films. Ohmic contacts to n-NCD films were formed by Ti/Au or Cr/Au metal electrodes. NCD based vibrating MEMS cantilever devices have been fabricated.