Electrical and optical properties of In2O3 nanoparticles prepared by MOCVD

High sensitive ozone sensors working at room temperature were demonstrated based on In₂O₃ nanoparticles, which were deposited by metal organic chemical vapor deposition (MOCVD). The resistance of the In₂O₃ particle containing layer can be tuned over five orders of magnitude after ultraviolet light illumination and oxidation by ozone containing gases. To investigate the light induced effect on In₂O₃ layer, In₂O₃ nanoparticles were deposited at different substrate temperatures by MOCVD and the electrical and optical properties of the layers were analyzed. It was found that the layers deposited above 220degC showed a typical linear IN behavior while the layers grown below 220degC revealed a classical Schottky behavior. Furthermore, the In₂O₃ layers deposited below the critical temperature demonstrated not only an increasing absorption at 3.7 eV, which is the optical band gap of In₂O₃ thin films, but also two additional absorption peaks located at ~43 and ~5.3 eV, respectively. These differences in structural, electrical and optical properties of In₂O₃ layers lead to different ozone sensing properties.