Ultrasensitive, Sustainable, and Selective Electrochemical Hydrazine Detection by ALD‐Developed Two‐Dimensional WO₃

Abstract

Wafer‐scale two‐dimensional (2D) WO3 films with different thicknesses of 0.78, 1.4, 3.6, and 6.5 nm were fabricated on Au‐SiO2/Si substrates using an atomic layer deposition technique. Their surface morphologies and chemical components were examined by field‐emission scanning electron microscopy, atomic force microscopy and X‐ray photoelectron spectroscopy. Cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy were utilized for the analysis of the electrochemical behavior of 2D WO3 films towards hydrazine detection under various conditions. The effect of the thickness of 2D WO3 on the electrochemical performance was also analyzed. Significant improvement in hydrazine sensing capabilities was obtained for monolayer 2D WO3 (0.78 nm), demonstrating a high sensitivity of 1.24 μA μM−1 cm−2, a linear hydrazine concentration detection ranging from 0.2 to 2100 μM, great long‐term stability, excellent selectivity and the lowest limit of detection of 0.015 μM reported to date, which provide a great potential method for materials fabrication in the development of high‐performance hydrazine detection.

Nanoscale Au-ZnO Heterostructure Developed by Atomic Layer Deposition Towards Amperometric H2O2 Detection

“…The correlated linear regression equation could be presented as follows: E P (V) = 0.0671 log ν + 0.278. For the diffusion-controlled process mentioned above, E P can be defined by the following Tafel equation [9]:…”

“…First of all, ALD is the only one technology, which enables fabrication of conformal, defect-free semiconductor 2D nano-films and their heterostructures on the wafer scale with precise control of their thickness during fabrication at the Ångstrom level [8]. In this regard, state-of-the-art nanoscale interfacing and molecular engineering of the sensing electrode materials can open up completely new possibilities by providing ultra-thin channels for key doping, minimization of the density of interfacial impurities and optimization of sensing capabilities of the devices [9]. Several recent reports about ALD-developed wafer-scaled monolayers of WO 3 [8,10,11] and TiO 2 [12,13] and few-layered MoO 3 [14,15], TiO 2 [16], and their heterojunctions including Au-WO 3 -TiO 2 [17], Ga 2 O 3 -WO 3 [18], Au-Ga 2 O 3 -TiO 2 [19], etc.…”

Plasma-induced sub-10 nm Au-SnO2-In2O3 heterostructures fabricated by atomic layer deposition for highly sensitive ethanol detection on ppm level

“…It has also been employed in modern different gas sensors [14][15][16]. In order to fabricate miniaturized and reliable SnO 2 -and In 2 O 3 -based hetero-structured SEs the following technological approaches have recently been proposed: sol-gel [17], solvothermal [18], microwave methods [19,20], spray pyrolysis [21], coaxial electrospinning [22], impregnation [23], hydrothermal deposition [24], ALD and PE-ALD [25][26][27][28][29], chemical vapor deposition (CVD) [30] and sputtering [31]. All these techniques can produce the SE crystalline size within the nm scale strengthening the influence of crystalline shape on the adsorption properties, which determine both gas sensitivity and selectivity.…”

“…Therefore, both shape and size of the developed nanocrystals regulate the type of binding to the SE surface and ultimately impact the amount of adsorbed gaseous species [13]. Among all fabrication techniques mentioned above, ALD or PE-ALD is a thin-film deposition method based on alternating, self-limiting chemical reactions between the gaseous precursors and solid substrate surface [26]. It can produce high quality, uniform and conformal SE even at the low fabrication temperatures [13,28,[31][32][33][34][35].…”

Functional Two-Dimensional Materials for Bioelectronic Neural Interfacing

“…These materials are expected to combine multiple sensing and stimulation functionalities and simultaneously create chronic biocompatible interfaces with neural cells and brain tissue. In this regard, 2D nanomaterials are among the main advanced atomically thin nanostructures that hold great promise for the development of highly active and miniaturized sensors [ 49 , 50 , 51 , 52 ]. Due to their high surface area, easy functionalization and exceptional electronic characteristics, 2D nanostructures are among the main options for the development of novel neural interface sensors [ 3 , 53 , 54 , 55 , 56 , 57 ].…”