A Complementary Silicon Quantum Dot-Enzyme Platform for Selective Detection of Nitroaromatics Compounds

To address the issue of poor selectivity in nanotechnology-driven, portable nitroaromatics sensors, we have coupled a ratiometric photoluminescence sensor based on silicon quantum dots and fluorescent proteins with a colorimetric enzyme-based sensor. Together, the sensors allow differentiation of nitroaromatic compounds – specifically, distinguishing acetylcholinergic nerve agents from the explosive compounds explored herein. The combined system can detect 2,4,6-trinitrotoluene, 2,4-dinitrotoluene and 4-nitrophenol with micromolar detection limits and affords subsequent differentiation from the nitro-containing nerve agent paraoxon. This demonstrates the advantage of merging elements of materials chemistry and biochemistry to devise customized sensors which can accurately identify hazardous chemical species.

A Complementary Silicon Quantum Dot-Enzyme Platform for Selective Detection of Nitroaromatics Compounds

To address the issue of poor selectivity in nanotechnology-driven, portable nitroaromatics sensors, we have coupled a ratiometric fluorescence sensor based on silicon quantum dots and fluorescent proteins with a colorimetric, enzyme-based sensor. Together, the sensors allow differentiation of nitroaromatic compounds – specifically, distinguishing acetylcholinergic nerve agents from the explosive compounds explored herein. The combined system can detect 2,4,6-trinitrotoluene, 2,4- dinitrotoluene and 4-nitrophenol with micromolar detection limits and affords subsequent differentiation from the nitro-containing nerve agent paraoxon. This demonstrates the advantage of merging elements of materials chemistry and biochemistry to devise customized sensors which can accurately identify hazardous chemical species.

Silicon: quantum dot photovoltage triodes

Silicon is widespread in modern electronics, but its electronic bandgap prevents the detection of infrared radiation at wavelengths above 1,100 nanometers, which limits its applications in multiple fields such as night vision, health monitoring and space navigation systems. It is therefore of interest to integrate silicon with infrared-sensitive materials to broaden its detection wavelength. Here we demonstrate a photovoltage triode that can use silicon as the emitter but is also sensitive to infrared spectra owing to the heterointegrated quantum dot light absorber. The photovoltage generated at the quantum dot base region, attracting holes from silicon, leads to high responsivity (exceeding 410 A·W−1 with Vbias of −1.5 V), and a widely self-tunable spectral response. Our device has the maximal specific detectivity (4.73 × 1013 Jones with Vbias of −0.4 V) at 1,550 nm among the infrared sensitized silicon detectors, which opens a new path towards infrared and visible imaging in one chip with silicon technology compatibility.

4.2 K sensitivity-tunable radio frequency reflectometry of a physically defined p-channel silicon quantum dot

We demonstrate the measurement of p-channel silicon-on-insulator quantum dots at liquid helium temperatures by using a radio frequency (rf) reflectometry circuit comprising of two independently tunable GaAs varactors. This arrangement allows observing Coulomb diamonds at 4.2 K under nearly best matching condition and optimal signal-to-noise ratio. We also discuss the rf leakage induced by the presence of the large top gate in MOS nanostructures and its consequence on the efficiency of rf-reflectometry. These results open the way to fast and sensitive readout in multi-gate architectures, including multi qubit platforms.