Application of Organophosphonic Acids by One-Step Supercritical CO₂ on 1D and 2D Semiconductors: Toward Enhanced Electrical and Sensing Performances

Abstract

Formation of dense monolayers with proven atmospheric stability using simple fabrication conditions remains a major challenge for potential applications such as (bio)sensors, solar cells, surfaces for growth of biological cells, and molecular, organic, and plastic electronics. Here, we demonstrate a single-step modification of organophosphonic acids (OPA) on 1D and 2D structures using supercritical carbon dioxide (SCCO2) as a processing medium, with high stability and significantly shorter processing times than those obtained by the conventional physisorption-chemisorption method (2.5 h vs 48-60 h).The advantages of this approach in terms of stability and atmospheric resistivity are demonstrated on various 2D materials, such as indium-tin-oxide (ITO) and 2D Si surfaces. The advantage of the reported approach on electronic and sensing devices is demonstrated by Si nanowire field effect transistors (SiNW FETs), which have shown a few orders of magnitude higher electrical and sensing performances, compared with devices obtained by conventional approaches. The compatibility of the reported approach with various materials and its simple implementation with a single reactor makes it easily scalable for various applications.

Integrated Strategy toward Self-Powering and Selectivity Tuning of Semiconductor Gas Sensors

“…Different bioinspired approaches have found their way into gas sensing applications due to the appealing analogies of both fields. , High selectivity toward a single gas species can be achieved via the binding of the analyte gas with free organic functional groups anchored on the sensor surface. In this respect, modifying the inorganic semiconductors surface with self-assembled monolayers (SAMs) has attracted increased interest in different fields of applications such as biosensors, biomolecular electronics, and gas sensors. − This can be attributed to their rich and tunable functionalities which can provide a selective binding interaction between these organic receptors and target molecular species. , The selective sensing using organic/inorganic interfaces was combined with the self-powering capabilities of inorganic heterostructures to produce a selective/self-powered gas sensor as recently reported by Hoffmann et al In this study, a self-powered organic/inorganic hybrid sensor (SAM/n-ZnO/p-Si) was fabricated and was capable of selective detection of NO 2 gas (TYPE-2 gas sensor). The resurgent demand for selective detection of nitrogen dioxide is due to its severe impacts on human health and environment. , Herein, theoretical calculations of work function changes are investigated to understand the effect of different SAMs on the TYPE-2 system.…”

“…High selectivity toward a single gas species can be achieved via the binding of the analyte gas with free organic functional groups anchored on the sensor surface. In this respect, modifying the inorganic semiconductors surface with self-assembled monolayers (SAMs) has attracted an increased interest in different fields of applications such as biosensors, biomolecular electronics, and gas sensors [9][10][11][12] . This can be attributed to their rich and tunable functionalities which can provide a selective binding interaction between these organic receptors and target molecular species 13,14 .…”

Carbonation Competing Functionalization on Calcium-Silicate-Hydrates: Investigation of Four Promising Surface-Activation Techniques

“…An alternative for successful chemical passivation would be the implementation of stronger acids in functionalization for example phosphonic acid. 54,55 Independently of the molecule destined to the functionalization of C-S-H phases, carbonates-free surfaces are desirable for the success of the passivation. Four different techniques were presented here to perform the removal of the carbonates that are acting as a barrier at the surface.…”

“…The chemical explanation for this barrier is the constant of dissociation of carboxylic acid, being much bigger than the one of silicic acid. , As a result, silicic acid can neither etch carbonates nor bind covalently to the carbonate surface. An alternative for successful chemical passivation would be the implementation of stronger acids in functionalization for example phosphonic acid. , …”

Mechanism of Phosphorus Transport Through Silicon Oxide During Phosphonic Acid Monolayer Doping

“…In this work, we investigate the feasibility of performing MLD directly on oxidized Si substrates using otherwise conventional SAM-grafting procedures followed by spike annealing. We used the well-characterized tethering by aggregation and growth (T-BAG) method for grafting of octadecylphosphonic acid (ODPA) on oxidized Si(111) surfaces , as a prototypical system for P-doping of Si using a SAM grafted onto its native oxide. In order to develop an overall picture of the MLD process, here we combine in situ infrared (IR) spectroscopy and X-ray photoelectron spectroscopy (XPS) with ex situ time-of-flight secondary ion mass spectrometry (ToF-SIMS) and impedance spectroscopy (IS), we experimentally monitor the chemical state of the adsorbed SAM, the electronic properties of the substrate, and the resulting diffusion profiles at every step of the annealing process.…”