Investigating the Impact of Deposition Parameters on the Biosensing Performance of Zinc Oxide Nanostructured Thin Films Fabricated via Vapor Phase Transport

Abstract

Despite huge advancements in biosensing technologies in the last few years, there remains a gap in comprehending the intricate relationship between growth parameters and the corresponding biosensing response characteristics. The present work investigates the correlation between the physical properties of ZnO thin films and their biosensing response to address this gap and further fabricate a urea sensor based on the optimized conditions. The Vapor Phase Transport (VPT) method was used to grow ZnO thin films, with biosensing performance observed to be highly dependent on growth conditions. Under optimal conditions, ZnO films demonstrated biosensing-friendly properties such as low stress, strong carrier mobility for electron transfer, and a large surface area for effective biomolecule loading. The prepared bioelectrode (Urs-GLDH/ZnO/Pt/Si) showed excellent performance in detecting urea with a high sensitivity of 41 μAmM−1cm−2 over a wide range of urea concentrations (5–200 mg dl−1 or 0.83–33.33 mM). The urea sensor also exhibited a low limit of detection (LOD) of 1.82 mg dl−1, a high shelf life lasting for 12 weeks, and superior selectivity. Thus, the present study not only aims at enhancing our understanding of the fundamental properties of ZnO thin films and their relation to processing conditions, but also emphasises their potential for enhanced biosensing applications.