Atomic Layer Deposition of Crystalline β-NiS for Superior Sensing in Thin-Film Non-Enzymatic Electrochemical Glucose Sensors

Rhombohedral nickel sulfide thin films were deposited on c-sapphire substrate via the atomic layer deposition (ALD) method using nickel acetylacetonate [Ni(acac)2] as nickel and H2S gas as sulfur precursors. The self-limiting nature of the ALD process is obtained in the temperature range of 200–240 °C, which provides crystalline NiS thin films without further annealing. A growth rate of ∼0.2 Å/cycle was observed at 200 °C. As-deposited thin films were studied for non-enzymatic electrochemical glucose sensing. The films exhibit an excellent sensitivity of 5.78 μA mM–1cm–2 and a low detection limit of 0.052 μM with a very small response time of <2 s.