Irradiation effect of synchrotron radiation on crystallization of thin amorphous WO3 film

In order to elucidate the effect of synchrotron radiation (SR) irradiation on crystal growth, crystallization of WO3 films has been performed in vacuum under SR irradiation. The main results were compared with the results of heat treatment of the same film. Upon SR irradiation for 80 s using a toroidal mirror, a catastrophic change occurred, i.e. W3O crystals (A-15 type) with a size of less than 30 nm appeared. Decomposition of the WO3 film started at above 750 degreesC during vacuum heating. W, WO2 and incommensurate WO3 crystals appeared. W3O crystal produced neither intense electron beam irradiation nor vacuum heating. These results will be discussed in terms of the differences caused by excitation with a SR beam, i.e. strong inner shell excitation and ionization of W and O may have taken place. (C) 2002 Elsevier Science B.V. All rights reserved.