Optical spectroscopy characterization of Cu doped ZnO nano- and microstructures grown by vapor-solid method

Fabrication and Characterization of ZnO:CuO Electronic Composites for Their Application in Sensing Processes

“…For n-type semiconductor exposed to a reducing atmosphere a decrease in the resistivity is expected, while the opposite should be observed for p-type materials, then either the different phases (Cu-rich or Zn-rich) dominate in the different regimes or, as it will be discussed later, a transition p-n sensing is produced. Similar differences have observed in a previous work in which different precursors were used to produce the Cu doped ZnO ceramics [17].…”

“…This combination opens a good opportunity to investigate the evolution of the sensing properties on moving from n-to p-type conductivity and the sensing properties of p-n junctions of different materials [14,15,16]. On the other hand, the large segregation effects observed in this system [17,18] gives us the opportunity to investigate the enhancement of sensing behaviour of the composites [19,20,21]. Finally, n-p junctions made with ZnO and CuO nanowires have shown to be a good option to control the selectivity of the sensor [10].…”

Study of the influence of the precursors on the sensing properties of ZnO:Cu system

“…With the exception of a couple of anomalous points in the sample doped with the highest Cu content, in all cases the sensitivity is higher for the lower gas concentrations. As shown in our previous work [28], segregation of copper to the grain boundaries occurs in all three samples regardless of their dopant concentration. However, they differ in the grain size since for the sample doped at 1% the grain size is between 2 and 7 µm, the sample doped at 5% has grain sizes between 5 and 15 µm, and the sample doped at 10% presents sizes between 15 and 20 µm.…”

“…This is the well-known green luminescence band of ZnO, usually attributed to V O. In addition, a wide band with components at around 550, 620 and 650 nm is also observed, they can be related to different point defects, such as V Zn , and to the presence of Cu ions [28]. The relative intensity of these components varies from the different samples and also changes with gas exposure.…”

Vapor-solid growth ZnO:ZrO2 micro and nanocomposites

“…Vapour Solid (VS) growth has shown to be a suitable method to obtain a large amount of microand nanostructures of both pure ZnO and doped with several transition metal [12,13] and rare earth ions [14,15] . In the case of ZrO2, the complex nature of the phase diagram which includes different phase transformations accompanied of volume changes suggest that the obtaining of pure or doped structures by this method will be difficult.…”