Development of Wide Bandgap Multifunctional NiO Nanostructures and Thin Films for Sensing Applications

Realizations of transparent pn homo-junction have become more important for the development of transparent electronics for the next-generation optoelectronic devices. The tunability of the electrical conductivity of NiO thin films with both P-type and N-type conduction by varying growth kinetics using RF sputtering technique with good optical and properties in the visible region have been demonstrated. The pn homo-junction of NiO thin films has been fabricated. The room-temperature conductivities for n-type and p-type NiO thin films have been studied using Hall measurement. Glancing angle deposition (GLAD) configuration of rf sputtering technique is utilized to fabricate the array of vertically align nanorods of NiO and are exploited for the development of homojunction devices. The fabricated homo-junction exhibits good rectifying behaviour with efficient ultra-violet (UV) photodiode characteristics, and providing suitable solution for the development of low-cost UV photo-detectors with enhanced response characteristics. The obtained results on the developed UV photo-detector will be elaborated.

 Further, Nickel oxide (NiO) nanoparticles (NiO-NPs) have been synthesized by a simple chemical route and exploited successfully for the fabrication of urea biosensors. A thin layer of NiO nanoparticles deposited on indium tin oxide (ITO) coated glass serves as efficient platform for the immobilisation of Urease (Ur) biomolecules for the detection of Urea. The array of NiO nanorods prepared by GLAD was also used as a matrix for making bio-electrode for the efficient detection of Urea using electrochemical techniques. The prepared amperometric bio-electrodes based on NiO nanostructures (Ur/NiO/ITO/glass) exhibits a high sensitivity of about 21.0 mA/(mM-cm²) and good linearity over a wide range (up to 16.65 Mm) of urea concentration.