Ultrasensitive detection of formaldehyde at room temperature using Si-chip assisted MOS/SiNWs nanocomposite based sensor

This work comprises the development of an ultrasensitive ZnO/SiNWs nanocomposite sensor for detecting formaldehyde (HCHO), an aldehyde whose presence in higher concentrations proves harmful to human health. Herein, ZnO as one of the metal oxide semiconductors (MOS) was used with silicon nanowires (SiNWs) to develop a sensor for precise detection of HCHO. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), Energy Dispersive X-Ray Analysis (EDX), Fourier transform infrared spectroscopy (FTIR), and X-ray Diffraction (XRD) were used to investigate the structural morphology and elemental analyses of the prepared nanocomposite structure. All these characterization studies revealed the uniform composition of ZnO/SiNWs nanocomposite structure. The sensing studies of HCHO at various concentrations were investigated at room temperature. The sensor response was found to be 1.27 with a highly accurate limit of detection (LoD) as (0.01 ppm). The developed ZnO/SiNWs sensor revealed high stability and repeatability, as well as fast response-recovery time. The well depicted sensing results at low concentrations could be attributed to the maximum adsorption of HCHO on the surface of ZnO/SiNWs structure due to high surface area, which was recorded to be 3-fold higher than that of the pristine ZnO based sensor. Hence, the findings and the developed sensor, that are being reported here can be used to reliably and precisely identify infections at an early stage.