Metal nano‐film resistivity chemical sensor

Abstract

In this work, we present a study on reusable thin metal film resistivity-based sensor for direct measurement of binding of thiol containing molecules in liquid samples. While in bulk conductors the DC current is not influenced by the surface events to a measureable degree in a thin metal layer the electrons close to the surface conduct a significant part of electricity and are influenced by the surface interactions. In this study, the thickness of the gold layer was kept below 100 nm resulting in easily measureable resistivity changes of the metal element upon a surface SH-groups binding. No further surface modifications were necessary. Thin film gold layers deposited on a glass substrate by vacuum sputtering were photolithographically structured into four sensing elements arranged in a Wheatstone bridge to compensate for resistance fluctuations due to the temperature changes. Concentrations as low 100 pM provided measureable signals. The surface after the measurement could be electrolytically regenerated for next measurements.

High Precision Experimental Exploration of Wheatstone Bridge Resistance Measurement

“…According to the principle of Wheatstone bridge, the box-type bridge, such as the QJ-23 box-type bridge, has been designed and sold in the market. At the same time, the self-organized bridge, which can also be used for measuring resistance, has become another aspect of Wheatstone bridge resistance measurement because of its distinctive designing concept and good accuracy [4][5][6][7].…”