resumo
Amorphous titanium dioxide-coated carbon nanotubes (CNTs) were prepared by atomic layer deposition (ALD) and investigated as sensing layers for resistive NO2 and O-2 gas sensors. By varying ALD process conditions and CNT structure, heterostructures with different metal oxide grain size, morphology and coating thickness were synthesized. Higher responses were observed with homogeneous and continuous 5.5 nm thick films onto CNTs at an operating temperature of 150 degrees C, while CNTs decorated with either discontinuous film or TiO2 nanoparticles showed a weak response close to the one of device made of bare CNTs. An unexpected p-type behavior in presence of the target gas was also noticed, independently of the metal oxide morphology and thickness. Based on previous works, hypotheses were made in order to explain the p-type behavior of TiO2/CNT sensors.
palavras-chave
ATOMIC LAYER DEPOSITION; METAL-OXIDES; ROOM-TEMPERATURE; THIN-FILMS; SENSORS; COMPOSITES; SNO2; NANOSTRUCTURES; NANOFIBERS; GRAPHENE
categoria
Science & Technology - Other Topics; Materials Science; Physics
autores
Marichy, C; Donato, N; Latino, M; Willinger, MG; Tessonnier, JP; Neri, G; Pinna, N
nossos autores
Catherine Marthe Dominique Marichy
Bolseiro de pós-DoutoramentoGrupos
Projectos
Nanotubes and Nanowires based hybrid nanostructures (PTDC/CTM/098361/2008)
Structural and chemical characterization at the nanometer scale (PTDC/CTM/100468/2008)
RMNE-UA-National Network of Electron Microscopy (REDE/1509/RME/2005 )
agradecimentos
This work was partially supported by the FCT projects (PTDC/CTM/098361/2008), (PTDC/CTM/100468/2008), and (REDE/1509/RME/2005) and the FCT grant (SFRH/BD/71453/2010).