Non-contact approach to extract Schottky barrier characteristics for gas sensitive nanostructured interfaces

Abstract

<p>Formation of high precision nanorod based surface morphologies can be engineered with nanotechnology to mimic the function of sensory hairs. Gas sensitive I-V characteristics unique to these surfaces require initialisation under voltage bias and temperature elevation to exploit their band structures and therefore achieve optimal gas response. Prior to detection, devising effective approaches to optimise nanorod based sensors can provide access and efficient control to downsize and significantly miniaturise current gas sensors. In this work, we devised a novel non-contact analysis approach via ultraviolet photoelectron spectroscopy (UPS) to extract specific band structure parameters specifically to locate particular bias for optimal sensor initialisation. The results from five cases all indicate how fabricated nanostructured Schottky barrier heights can be evaluated from UPS data and how their I-V data are correlated and also validate our band structure postulations. The obtained Schottky barrier height values from simulated band structures provided an optimal biasing condition of 0.8 V for Au-ZnO nanorod hydrogen gas sensory operation at 150 degrees C, demonstrating experimental validity with gaselectrical measurements. Further, the gas response data show exponential dependence with gas concentration which is highly relevant for programmable trigger response controlled sensing function based applications.</p>