Using the ArF excimer laser-induced MOCVD method, InN x O y thin films are grown on a glass substrate. The photolytical decomposition of NH 3 enables to grow them even at room temperature. It is found that the InN x O y thin films grown at a temperature less than 250 1C show an excellent photocatalytic decomposition of H 2 S under UV irradiation, while the activity of the films grown at a temperature higher than 300 1C is very small, less than 1 4 of that for the low-temperature films. The excellent photocatalytic activity for the low-temperature films is closely related to the amorphous phase of the films. r

In this paper, the employment of the ArF excimer‐laser assisted nitridation of sapphire substrate is studied in the ArF‐laser assisted MOVPE (la‐MOVPE) of InN. An ArF excimer laser with an energy 50 mJ/pulse and a repetition rate 20 Hz is introduced parallel to the substrate surface. The surface morphology of InN film grown on α‐Al2O3 (0001) is found to be markedly dependent on the nitridation conditions for the sapphire substrate. When no nitridation is made, the surface of grown InN film is very rough and many In droplets are found on it. A film with a mixture of rough‐surface region with In droplets and smooth‐surface region is grown on the thermally‐nitrided substrate (1000 °C for 30 min). By employing the ArF‐laser irradiation to the NH3 flow during the substrate nitridation at 1000 °C for 30 min (la‐nitridation), a smooth surface region is expanded to the entire surface of film. The smooth surface is found to be stable at growth temperature higher than 700 °C. The KOH etching of grown films reveals that the smooth surface has 5–10 time higher etching rate than the rough one. From these facts, it is concluded that the film with the smooth surface has N‐polarity. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)