, Volume 65, Issue 5, pp 949–958

Structural, electrical and gas-sensing properties of In2O3 : Ag composite nanoparticle layers

  • B. R. Mehta
  • V. N. Singh

DOI: 10.1007/BF02704096

Cite this article as:
Mehta, B.R. & Singh, V.N. Pramana - J Phys (2005) 65: 949. doi:10.1007/BF02704096


The central objective of this study is to investigate (i) size-dependent properties of In2O3 nanoparticles and (ii) the role of metal additives in enhancing the gas sensing response. For this purpose, In2O3 : Ag composite nanoparticle layers having welldefined individual nanoparticle size and composition have been grown by a two step synthesis method. Thermogravimetric analysis, X-ray diffraction and transmission electron microscopy have been used to study the effect of post-synthesis heat treatment on the size and structure of the nanoparticles. A first-time unambiguous observation of sizedependent lowering of transformation temperature has been explained in terms of lower cohesive energy of surface atoms and increase in surface-to-volume ratio with decrease in nanoparticle size. The gas sensing studies of In2O3 as well as the In2O3 : Ag composite nanoparticle layers have been studied as a function of size and composition. In2O3: Ag composite nanoparticle layers with 15% silver show a sensitivity of 436 and response time of 6 s for 1000 ppm of ethanol in air. Ag additives form a p-type Ag2O, which interact with n-type In2O3 to produce an electron-deficient space-charge layer. In the presence of ethanol, interfacial Ag2O reduces to Ag, creating an accumulation layer in In2O3 resulting in increased sensitivity


In2O3 nanoparticlesAg nanoparticlesgas sensorcomposite nanoparticles



Copyright information

© Indian Academy of Sciences 2005

Authors and Affiliations

  • B. R. Mehta
    • 1
  • V. N. Singh
    • 1
  1. 1.Thin Film Laboratory, Department of PhysicsIndian Institute of Technology DelhiNew DelhiIndia