Hydrothermal Growth of Zinc Oxide (ZnO) Nanorods (NRs) on Screen Printed IDEs for pH Measurement Application

Akshaya Kumar A,Shekhar Bhansali,Naveen Kumar S K,Renny Edwin Fernandez,Almaw Ayele Aniley

doi:10.1149/2.0431909jes

Abstract

There is considerable interest in nanostructured materials with interdigitated electrodes (IDEs) platforms to detect and monitor the level of various ions in numerous applications. Herein, we report the design and fabrication of IDEs based pH sensor by using hydrothermal growth of ZnO nanorods (NRs). A four-step deposition of ZnO seed layer followed by a hydrothermal treatment lead to the heavily ordered ZnO NRs patterns on the screen printed IDEs. The structural, chemical compositional and electrical properties of the NRs were investigated and examined by using field emission scanning electron microscopy (FeSEM), atomic force microscopy (AFM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) technique and Keithley 4200 semiconductor characterization system respectively. The sensor capacitance and pH were found to be inversely proportional at a working frequency of 1 kHz. The sensor displayed sensitivity of 1.06 nF/pH in the range of pH 4−10.

Highlights

Numerous attempts have been made to detect the pH concentration using different methods like glass probe based pH electrodes,[9] ion selective electrodes (ISEs)[10,11], ion selective field effect transistor (ISFET) pH sensors[12,4] need pre conditionally prepared samples in laboratories, there is a time delay in processing and it will cause to the decreases in sensor detection performance
We present a fabrication of Zinc oxide (ZnO) NR based interdigitated electrodes (IDEs) sensor for continuous electrochemical detection of pH
The structural, compositional and electrical properties were investigated with field emission scanning electron microscopy (FeSEM), atomic force microscopy (AFM) energy dispersive spectroscopy (EDS), Xray diffraction (XRD) technique and Keithley 4200 semiconductor

Summary

Introduction

PH is a crucial parameter in regulating the reactivity of many chemical physical and biological species, its measurement is fundamental need in many fields ranging from agriculture[1,2] and environmental science to chemical engineering[3] and food science to biology and health applications.[4,5,6,7,8] Numerous attempts have been made to detect the pH concentration using different methods like glass probe based pH electrodes,[9] ion selective electrodes (ISEs)[10,11], ion selective field effect transistor (ISFET) pH sensors[12,4] need pre conditionally prepared samples in laboratories, there is a time delay in processing and it will cause to the decreases in sensor detection performance. Zinc oxide (ZnO) is more versatile and widely studied metal oxide material due to easy synthesis method at room temperature and which exhibits the excellent physical, chemical, electrical and optoelectronic properties. One-dimensional (1D) Zinc oxide (ZnO) which has a direct wide bandgap (3.37eV) semiconductor with a large excitation binding energy (60 meV) at room temperature. The IDE surface was modified with the active layer of ZnO seed particle, further enhance the seed particle into the ZnO NRs. The structural, compositional and electrical properties were investigated with field emission scanning electron microscopy (FeSEM), atomic force microscopy (AFM) energy dispersive spectroscopy (EDS), Xray diffraction (XRD) technique and Keithley 4200 semiconductor

Methods

Results

Conclusion