Polycrystalline and amorphous sol-gel derived WO/sub 3/ thin films and their gas sensing properties
COMMAD 2000 Proceedings. Conference on Optoelectronic and Microelectronic Materials and Devices - Trang 206-209
Tóm tắt
Amorphous and polycrystalline tungsten trioxide (WO/sub 3/) thin films were prepared using the sol-gel process. Tungsten ethoxide was used as precursor material. The WO/sub 3/ thin films were spun onto the sapphire and silicon substrates at 2500 rpm for 30 s. The X-ray diffraction (XRD) results revealed that the films annealed at low temperature of 420/spl deg/C for 1 hr. are amorphous while those annealed at as high as 500/spl deg/C are polycrystalline. The scanning electronic microscope (SEM) images revealed that the film annealed at 360/spl deg/C was amorphous and the surface was smooth. The film showed good responses to 100 ppm, 1000 ppm and 1% O/sub 2/ at an operating temperature of 170/spl deg/C. At high operating temperatures the films showed unsaturated and sluggish responses to oxygen gas. The amorphous WO/sub 3/ thin films showed no response to ozone. The crystallized thin films showed very stable response to oxygen.
Từ khóa
#Amorphous materials #Transistors #Annealing #Temperature #Tungsten #Scanning electron microscopy #Semiconductor thin films #Silicon #Substrates #X-ray imagingTài liệu tham khảo
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