Ultrathin Silicon Nanowires for Optical and Electrical Nitrogen Dioxide Detection.

Dario Morganti,Paolo Musumeci,Barbara Fazio,Gianluca Leonardi,Giovanni Neri,Antonio Alessio Leonardi,Patrizia Livreri,Gabriele Salvato,Maria José Lo Faro,Sabrina Conoci,Alessia Irrera

doi:10.3390/nano11071767

Abstract

The ever-stronger attention paid to enhancing safety in the workplace has led to novel sensor development and improvement. Despite the technological progress, nanostructured sensors are not being commercially transferred due to expensive and non-microelectronic compatible materials and processing approaches. In this paper, the realization of a cost-effective sensor based on ultrathin silicon nanowires (Si NWs) for the detection of nitrogen dioxide (NO2) is reported. A modification of the metal-assisted chemical etching method allows light-emitting silicon nanowires to be obtained through a fast, low-cost, and industrially compatible approach. NO2 is a well-known dangerous gas that, even with a small concentration of 3 ppm, represents a serious hazard for human health. We exploit the particular optical and electrical properties of these Si NWs to reveal low NO2 concentrations through their photoluminescence (PL) and resistance variations reaching 2 ppm of NO2. Indeed, these Si NWs offer a fast response and reversibility with both electrical and optical transductions. Despite the macro contacts affecting the electrical transduction, the sensing performances are of high interest for further developments. These promising performances coupled with the scalable Si NW synthesis could unfold opportunities for smaller sized and better performing sensors reaching the market for environmental monitoring.

Highlights

We present a novel gas sensing solution based on room temperature (RT) luminescent Si
silicon nanowires (Si NWs) prepared using the previously discussed Metal-Assisted Chemical Etching (MACE) technique have been tested as a novel gas sensing platform
We have focused our efforts on the detection of nitrogen dioxide, which is a forefront field for the development of increasingly sensitive and efficient sensors in monitoring the safety of both urban and closed environments

Summary

Introduction

The interest of the scientific community and industry in gas detection has continuously become more important since the industrial revolution. The birth of the industry was followed by an exponential production of different toxic gas such as CO, CO2 , NOx , NH3 , and several hydrocarbon compounds. Due to the effects of these toxic gases on human health, gas detection started to become a priority demand. Gas sensors play an important role in many applications, from industrial air quality monitoring to novel automotive, and smart city applications [1,2,3,4,5,6].

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Conclusion