B. R. Mehta — новинки

Transparent conducting oxides (TCO's) have drawn great attention owing to their high electrical conductivity (10,000 S/cm) and high transparency (80-90%) in the visible region. This combination of properties makes them suitable for a number of applications such as solar cells, LCD display, OPV devices and even transparent electronics. The TCO nanostructures even showed better transparent contact than TCO thin film. High surface-to-volume ratio of nanostructures have demonstrated high sensitivity towards various target gases like NH3, CO, H2 and H2S and for NO2, which is one of the most dangerous air pollutants that causes acid rain and holes in ozone layer. To realize these applications, a basic understanding of the growth mechanism of nanostructures is a key requirement. Here, the main focus is given for tunable growth of indium oxide nanostructures and their applications. The indium metal filled indium oxide nanotube based nanorocket and indium mass transport in indium oxide nanotubes is demonstrated with the help of high-resolution transmission electron microscopy.

Gas-sensing properties of oxide semiconductors improves by using then in nanocrystalline forms. The sensitivity of gas-sensor has also been modified by adding metals or metal oxides as catalytic agents. Using the In2O3 and Ag nanoparticles as the precursor; In2O3: Ag composite nanoparticle layers have been grown. It has been demonstrated that a decreasing particle size leads to an increased sensitivity and a decreased response time. At C2H5OH concentration of 1000 ppm in air and at an operating temperature of 400°C, sensitivity and response time of 325 and 8 s, respectively have been achieved in case of In2O3 nanoparticles with a size of 14 nm. With the addition of 15% silver, response time of 6 s and sensitivity of 436 has been obtained for 1000 ppm ethanol at 400°C. Ag2O nanoparticle draws electrons from the In2O3 layer and enhances the formation of electron-depleted layer. On exposure to a reducing gas, interfacial Ag2O is reduced to Ag, with a decrease or disappearance of the space-charge layer. Gas sensing response thus depends on the change in depletion layer in interface from Ag2O-In2O3 to accumulation layer in Ag-In2O3.