DataSheet1_Analysis of synthesized doped vertical silicon nanowire arrays for effective sensing of nitrogen dioxide: As gas sensors.pdf

In the present study, the controllable fabrication of silicon nanowires (Si NWs) with vertical alignment was accomplished using metal assisted chemical etching (MACE). The different characteristics, such as structural, morphological, chemical, optical, and dielectric properties were analyzed using X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), Raman spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy (UV-DRS), and LCR [inductance (L), capacitance (C), and resistance (R)] meter (volume of the gas-sensing chamber is 650 mm3). It was revealed from the morphological study i.e., from the FESEM that p-type Si NWs are smaller in size than n-type Si NWs which is attributable to the energy band gap. The optical band gap (Eg) is observed to increase from 1.64 to 1.89 eV with the decreasing of the crystallite size and the optical reflection spectra of the Si NWs show a shift toward a lower wavelength (blue shift). Moreover, Raman spectra verified the red-shifted, asymmetrically broadened Raman line-shapes, which provides information about the size confinement effect in Si NWs. The MACE approach is excellent for synthesizing nanowire structures for use in gas-sensing applications due to its flexibility. The sensitivity of synthesized Si NWs was tested for NO2 gas. The sensor method is unique based on the testing of the device in the presence of a test gas because the use of the gas-sensing setup has the potential to measure the change in resistance by varying frequency, temperature, and time.

在本项研究中，通过金属辅助化学腐蚀法（MACE）实现了具有垂直排列的硅纳米线（Si NWs）的可控制备。利用X射线衍射（XRD）、场发射扫描电子显微镜（FESEM）、拉曼光谱、紫外-可见漫反射光谱（UV-DRS）以及LCR [电感（L）、电容（C）和电阻（R）]计（气体传感腔体积为650 mm3）对不同的特性，包括结构、形态、化学、光学和介电性质进行了分析。形态学研究，即从场发射扫描电子显微镜中观察，发现p型Si NWs的尺寸小于n型Si NWs，这是由于能带间隙所致。随着晶粒尺寸的减小，光学带隙（Eg）从1.64 eV增加到1.89 eV，Si NWs的光学反射光谱显示出向较低波长的偏移（蓝移）。此外，拉曼光谱验证了红移的、非对称展宽的拉曼线条形状，这为Si NWs中的尺寸限制效应提供了信息。MACE方法因其灵活性而非常适合用于合成纳米线结构，用于气体传感应用。对合成的Si NWs的敏感性进行了对NO2气体的测试。基于在测试气体存在下对器件进行测试的独特传感器方法，因为气体传感装置的使用有可能通过改变频率、温度和时间来测量电阻的变化。