Gas Sensing And Photoluminescence Of Multiple Heterostructure Composites

Nowadays, the development of science and technology has promoted the rapid improvement of economy. At the same time, it also will give rise to many problems of the human living environment. In recent years, various poisonous gases, such as auto exhausts and industrial waste gas, have a great effect on the environment. The development of gas sensors, which can detect a variety of target gas quickly and accurately, is one of the important tasks of scientific research. Key requirements for chemical sensors should contain characteristics of high sensitivity and good selectivity to a trace targeted gas with excellent stability at mild temperature. Therefore, the research of new type materials for visible-light-enhanced gas sensing is rising today. This thesis included the following three aspects:(1) Here CdSxSe1-x nanoribbons were successfully synthesized with a gold-catalyzed physical evaporation method. The high aspect ratio and surface-volume ratio would remarkably promote the carrier transfer on the surface of CdSxSe1-x nanoribbons. And the samples exhibited significant response to visible light. The optimum operating temperature of CdSxSe1-x-based gas sensors in the dark was 200 oC, while it reduced by approximately 100 oC when under visible light irradiation. In particular, CdSxSe1-x nanoribbons were employed in the fabrication of visible-light-activated gas sensors to detect acetic acid at room temperature.(2) Based on the above work, CdSxSe1-x nanoribbons were synthesized by a simple physical deposition method in a high-temperature tube furnace, with the composition(x value) being tuned through controlling the experimental conditions. The microscopic PL under continuous-wave excitation of a single CdSxSe1-x nanoribbon was investigated and compared with two content(x value of 0.47 and 0.79). The results showed the dependence of PL intensity on the excitation power.(3) We successfully realized a one-dimensional(1D) composition grading quaternary ZnxCd1-xSySe1-y nanoribbons using CdSe and ZnS as raw materials. And four samples were choosed in this experiment. The results showed that ZnxCd1-xSySe1-y nanoribbons exhibited a single emission peak and the PL peaks basically remained at their position and only changed from about 677 nm to 585 nm. The unique material platform achieved will open a wide range of applications from full spectrum solar cells, multispectral detectors, or spectrometer on-a-chip to superbroadly tunable nanolasers.