Department of Photonics, National Cheng Kung University, Tainan 701, Taiwan, Republic of China.
Program on Key Materials, Academy of Innovative Semiconductor and Sustainable Manufacturing, National Cheng Kung University, Tainan 701, Taiwan, Republic of China.
ACS Sens. 2024 Jan 26;9(1):118-125. doi: 10.1021/acssensors.3c01742. Epub 2023 Dec 27.
In this work, a vapor cooling condensation system was utilized to deposit various amounts of p-type gold-black nanoparticles (NPs) onto the surface of n-type gallium oxide (GaO) nanorods forming p-n heterojunction-structured sensing membranes of nitrogen dioxide (NO) gas sensors. The role and the sensing mechanism of the various gold-black NP-decorated GaO nanorods in NO gas sensors were investigated. The coverage and atomic percentage of the sensing membranes were observed using high-resolution transmission electron microscopy (HRTEM) measurements and energy-dispersive spectroscopy (EDS), respectively. For the NO gas sensor using the sensing membrane of 60 s-deposited gold-black NP-decorated GaO nanorods under a NO concentration of 10 ppm, the highest responsivity of 5221.1% was obtained. This result was attributed to the spillover effect and the formation of the p-n heterojunction, which increased more ionized-oxygen adsorption sites and promoted the reaction between NO gas and GaO nanorods. Furthermore, the NO gas sensor could detect the low NO concentration of 100 ppb and achieved a responsivity of 56.9%. The resulting NO gas sensor also exhibited excellent selectivity for detecting NO gas, with higher responsivity at a NO concentration of 10 ppm compared with that of the CHOH and NH concentrations of 100 ppm.
在这项工作中，利用蒸气冷却冷凝系统将不同量的 p 型金黑纳米颗粒 (NPs) 沉积到 n 型氧化镓 (GaO) 纳米棒的表面上，形成二氧化氮 (NO) 气体传感器的 p-n 异质结结构感测膜。研究了各种金黑 NP 修饰的 GaO 纳米棒在 NO 气体传感器中的作用和传感机制。使用高分辨率透射电子显微镜 (HRTEM) 测量和能量色散光谱 (EDS) 分别观察了覆盖率和感测膜的原子百分比。对于在 10 ppm NO 浓度下使用沉积 60 秒的金黑 NP 修饰的 GaO 纳米棒的感测膜的 NO 气体传感器，获得了最高响应值 5221.1%。这一结果归因于溢流效应和 p-n 异质结的形成，这增加了更多的离子化氧吸附位，并促进了 NO 气体与 GaO 纳米棒之间的反应。此外，NO 气体传感器可以检测低浓度的 100 ppb 的 NO，响应值达到 56.9%。所得的 NO 气体传感器还表现出对检测 NO 气体的优异选择性，在 10 ppm 的 NO 浓度下的响应值比 100 ppm 的 CHOH 和 NH 浓度下的响应值更高。
