Trace Explosive Sensor Devices Based on Semiconductor Nanomaterials

Abstract

This dissertation discusses an explosive sensing device based on semiconductor nanomaterials. Here, we mainly focus on two kinds of materials: titanium dioxide nanowires and silicon nanowires to detect explosive trace vapor. Herein, methods for the synthesis, fabrication, design of nanostructured sensing materials using low-cost hydrothermal process are present. In addition, the nanomaterials have been systemically tested on different explosive. The first part of dissertation is focused on the fabrication of TiO2(B) dominant nanowires and testing the response to explosives. It was found that the high porous TiO2(B) nanowires when mixed anatase TiO2, exhibit a very fast and highly sensitive response to nitro-containing explosives. The second part of dissertation has studied the basic sensing mechanism of TiO2(B) nanowire sensor to detect explosives. It shows the specific surface characteristics of TiO2 responsible for the nitro-containing explosives. This information is then used to propose a method using UV illumination to reduce the effect of water vapor on TiO2(B) nanowires. The third part discussed an explosive sensor based on silicon nanowires. We analyzed the mechanism of silicon nanowires to detect nitro-related explosive compounds. In order to further investigate the sensing mechanism of TiO2, the fourth part of dissertation studies the effect on sensor performance by using different crystal phases of TiO2, different microstructure of TiO2, surface modification of TiO2, and different kinds of nanostructured semiconductors such as ZnO nanowires, TiO2 coated ZnO nanowires, V2O5 nanowires, and CdS nanowires to detect explosives. It is found that only TiO2 related semiconductor shows good response to explosives.