- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Nitrogen oxides sensing performance of thiols and dithiols self-assembled monolayer functionalized Au/GaAs-based Schottky diodes
摘要： In this work, GaAs-based Schottky diodes, functionalized by alkanethiolates, were used to fabricate NOx gas sensors with high-selectivity and low-power. Alkanethiolates were employed to form a self-assembled monolayer (SAM) on the surface of the Au (111) Schottky contacts of the n-GaAs substrate using immersion method. The adsorption behaviors between SAM and Au (111) with different terminal (functional) groups, carbon numbers (CN), immersion times (tim), and alkanedithiol concentrations were characterized by cyclic voltammetry (CV) measurement. The interaction between NOx molecules and SAM was determined by an ultraviolet/visible (UV-Vis) spectrophotometer. The NOx sensing performance of the studied device under proper conditions was investigated at different temperatures and NOx gas concentrations. Experimentally, at 25℃, good sensing responses of 49.6 and 35.5 in 100 ppm NO2 and NO ambiences were obtained, respectively. Furthermore, similar sensing properties of the studied device were found in air and in N2 ambience. Therefore, the studied device can be considered a promising candidate for NOx sensing applications.
关键词： Alkanedithiol,Nitrogen oxides,Gas sensors,Schottky diode,GaAs,Self-assembled monolayers (SAM)
更新于2025-09-12 10:27:22
-
High-selectivity NOx sensors based on an Au/InGaP Schottky diode functionalized with self-assembled monolayer of alkanedithiols
摘要： This work was devoted to fabricating high-selectivity NOx gas sensors based on an Au/InGaP Schottky diode. In order to enhance the sensing selectivity and sensing response, a self-assembled monolayer (SAM) of alkanedithiol was used to modify the Schottky contact with an S-Au covalent bond based on the self-assembled property and terminal functional group. The studied SAM/Au/InGaP Schottky diodes were fabricated by semiconductor processes and immersion treatment. The effects of the carbon number (CN) of SAM, the SAM immersion time, and immersion dithiol concentrations were comprehensively studied in this work. In addition, the selectivity and sensing performance of dithiol functionalized Au/InGaP Schottky diodes under different temperatures and NOx concentrations were studied for comparison. In order to obtain the optimal NOx sensing performance, cyclic voltammetry (CV) was employed to study the self-assembled performance of the dithiol monolayer on the Au surface. The sensing responses of 16.5 and 7.2 were obtained under 100 ppm NO2/N2 and NO/N2 at 30oC, respectively, for the studied 1,10-decanedithiol (DDT)/Au/InGaP device. Moreover, compared to other sensing gases, the DDT/Au/InGaP sensing device showed high selectivity toward NOx gas. Furthermore, the theoretical first-order kinetic and thermodynamic theoretical analysis were consistent with the experimental transient and steady-state sensing results. Therefore, the studied SAM/Au/InGaP Schottky diode demonstrated promising results for NOx sensing applications.
关键词： Nitrogen oxides,Gas sensors,Schottky diode,Self-assembled monolayers (SAM),InGaP,Alkanedithiol
更新于2025-09-12 10:27:22
-
ZnO-coated SiO2 nanocatalyst preparation and its photocatalytic activity over nitric oxides as an alternative material to pure ZnO
摘要： Core-shell nanospheres, CSNp, consisting of silica as a core and zinc oxide as a shell were prepared via a simple and environmentally friendly procedure. Silica cores with a mean diameter of 300 nm were prepared through the hydrolysis-condensation reactions in the presence of hyperbranched poly(ethylene)imine (HBPEI) followed by calcination and chemical surface modi?cation with the use of HBPEI. To fabricate the core-shell structure, various amounts of zinc nitrate hexahydrate were precipitated using the carboxymethyl poly(ethylene)imine polymer (Trilon P) as a precipitator. To this suspension, the as synthesized modi?ed silica powder was added with the aim to develop electrostatic bonds between the carboxyl groups of TRILON P and the amino groups of the cationic HBPEI polymer. The optimization of processing parameters led to the development of homogeneous core-shell structures bearing a well-developed nanocrystalline zinc oxide shell over each silica core. The material with the optimum shell showed excellent photocatalytic activity over nitric oxides as the photocatalytic yield reached 72.9%.
关键词： Core-shell,Photocatalysis,Silicon oxide,Nitrogen oxides,Zinc oxide
更新于2025-09-04 15:30:14