Amorphous WO3 films have been deposited by E-beam evaporation technique at
a substrate temperature of 80 degreesC using different base pressure values
. The best results have been obtained starting from a mild base pressure (1
x 10(-5) Torr) probably due to the presence of water and oxidative atmosph
ere in the evaporation chamber. TEM investigations have shown that thermall
y evaporated WO3 films have an amorphous metastable structure, which subjec
ted to energetic solicitations changes towards a nanocrystalline phase. The
amorphous material subsequently annealed at a temperature of 500 degreesC
exhibits a fully crystalline structure. Also, in this case good electrochro
mic properties have been observed. Afterwards a WO3 double layer structure
has been realised depositing an amorphous him upon a crystalline layer. The
amorphous/crystalline structure properties have been compared with the amo
rphous and crystalline single layer ones. The colouration response and the
transmittance asymptotic value during the bleaching phase have been better
for the double layer. (C) 2001 Elsevier Science Ltd. All rights reserved.