Synthesis and Characterization of ZnO Nano Discs Using Wet Chemical Method for Sensing Applications

Fabrication of novel sensing devices using nano structured semiconducting metal oxide (SMO) is gaining prominence in research in recent years due to its notable properties and reduced cost. Among various SMO like ZnO, SnO2, TiO2, In2O3 etc., ZnO is one of the most promising nanomaterial due to its unique properties and when synthesised in various size and morphology can be used for various applications. In this paper, we report the synthesis and characterization of well aligned ZnO (Zinc Oxide) nano discs using wet chemical process. Wet - Chemical synthesis has emerged as one of the most promising technique towards high-yield and mass production of nanoparticles of desired particle size, shape and size distributions. The synthesized nanoparticles were characterized for its optical characteristics using UV-Visible spectrophotometer, for structural and compositional studies by XRD, FESEM and EDX. CV (Capacitance-Voltage) characteristics on ZnO based MOM (Metal oxide Metal) and MOS (Metal oxide Semiconductor) structure were studied using Impedance analyser. The XRD showed the peak intensity as 4270.23 at 2 theta equal to 36.2095 degrees with FWHM (Full Width Half Maximum) as 0.2453. EDX results showed the sample in pure ZnO phase. The images obtained from FESEM showed a uniform hexagonal disc type structure of approximately 100 nm in diameter and 30-40 nm in thickness. UV absorption peak was observed at 357nm. Sensing property of ZnO highly depends on its size and structure. C-V curves of ZnO based MOS contact showed 3 prominent regions: accumulation, depletion and inversion. C-V curves of MOM contact at 500 Hz behaved like a tunable capacitor. This variation of capacitance with respect to applied voltage exhibited by the MOM sample can be used for biomedical sensing applications to harness bio potential signals generated by the human body. These bio potentials can be sensed using surface electrodes which can show proportional varying sensing parameters like surfaces resistance, capacitance etc. (C) 2017 Elsevier Ltd. All rights reserved.