Sains Malaysiana 41(8)(2012): 1029–1035

Effect of Different TiO₂ Preparation Techniques on the Performance of the

Dielectric Bolometer Ba₀₆Sr_0.4TiO₃ as a Distance Sensor

(Kesan Kaedah Penyediaan TiO₂ yang Berbeza Terhadap Prestasi Bolometer

Dielektrik Ba₀₆Sr_0.4TiO₃ sebagai Pengesan Jarak)

N.B. Ibrahim*, E. Yusrianto & Z. Ibarahim

School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia

43600 Bangi, Selangor, Malaysia

Received: 25 January 2010 / Accepted: 25 March 2011

ABSTRACT

In this study TiO₂ films have been prepared using two different techniques i.e. sol-gel and electron gun evaporation (e-gun) techniques. The films were annealed at 300, 350 and 400^oC in air. The microstructure study using field emission scanning electron microscopy and x-ray diffractometer showed nanometer grains size and only the film prepared by sol-gel and annealed at 400^oC has anatase phase while others are amorphous. To study the effect of the films (as buffer layer) onto the dielectric bolometer Ba_0.6Sr_0.4TiO₃ as distance sensor, sensors with the configuration of Al/BST/TiO₂/RuO₂/SiO₂/Si were built. Two different measurements i.e. with and without infrared source were carried out to measure the sensitivity and repeatability of the sensors. The sensors which contained sol-gel TiO2 films gave reading for both type of measurements, indicating that the sensor can act as active and passive sensors. However, the sensors which contained e-gun TiO₂ films only gave responses when the IR source was used, indicating that they can only act as passive sensors. The most sensitive sensor was TiO₂ film prepared by sol gel and annealed at 350^oC. In general sensors which contained TiO₂ films prepared by sol gel showed good repeatability.

Keywords: Sol-gel; thin film; TiO₂

ABSTRAK

Dalam kajian ini, filem TiO₂ telah disediakan dengan dua teknik yang berbeza iaitu teknik sol-gel dan penyejatan senapang elektron (senapang-e). Filem kemudiannya disepuhlindap pada 300, 350 dan 400^oC dalam udara biasa. Kajian mikrostruktur menggunakan mikroskop elektron imbasan pemancaran medan (FE-SEM) dan pembelauan sinar-X menunjukkan kesemua filem mempunyai saiz butiran nanometer dan hanya filem yang disediakan dengan sol-gel dan disepuhindap pada 400^oC mempunyai fasa anatas sementara yang lain adalah amorfus. Untuk mengkaji kesan filem tersebut (sebagai lapisan penimbal) ke atas bolometer dielektrik Ba_0.6Sr_0.4TiO₃ sebagai pengesan jarak, sensor dengan konfigurasi Al/BST/TiO₂/RuO₂/SiO₂/Si telah dibina. Dua pengukuran yang berbeza iaitu dengan dan tanpa punca inframerah telah dijalankan untuk mengukur kesensitifan dan kebolehulangan pengesan. Pengesan yang mengandungi filem TiO₂ sol-gel memberikan bacaan untuk kedua-dua jenis pengukuran, menandakan pengesan ini boleh bertindak sebagai pengesan aktif dan pasif. Namun begitu, pengesan yang mengandungi filem TiO₂ senapang-e hanya memberi tindak balas apabila punca inframerah digunakan, menandakan pengesan hanya boleh bertindak sebagai pengesan pasif. Pengesan yang paling sensitif adalah pengesan dengan filem TiO₂ yang disediakan dengan sol-gel dan disepuhindap pada 350^oC. Secara amnya pengesan yang mengandungi filem TiO₂ yang disediakan dengan sol-gel menunjukkan kebolehulangan yang baik.

Kata kunci: Filem nipis; sol-gel; TiO₂

REFERENCES

Brinker, C.J. & Scherer, G.W. 1990. Sol-Gel Science: The Physics and Chemistry of Sol-Gel Processing. New York: Academic Press.

Chen, L., Shen, M., Fang, L. & Xu, Y. 2008. Microstructure control of (Pb,Sr)TiO₃ films on Pt/Ti/SiO₂/Si substrates by a TiO₂ buffer layer. Thin Solid Films 516: 1285-1289.

Dewi, R., Baa’yah, N.I. & Talib, I.A. 2007. The effect of spin coating rate on the microstructure, grain size, surface roughness and thickness of Ba_0.6Sr_0.4TiO₃ thin film prepared by the sol-gel process. Materials Science-Poland 25(3): 657-662.

Dewi, R. 2009. Distance sensor based on nanoparticles of barium strontium titanate. PhD Thesis. Universiti Kebangsaan Malaysia, Bangi (unpublished).

Efil Yusrianto, Noor Baa’yah Ibrahim & Zahari Ibarahim. 2010. The effect of TiO₂ thin films on the sensitivity, repeatability and current density of the dielectric bolometer Ba_0.6Sr_0.4TiO₃ as a distance sensor. Solid State Science and Technology 18(2) 52-60.

Fan, Y., Yu, S., Sun, R., Li, L, Du, R. & Yin, Y. 2009. Microstructure and electrical properties of Ba_0.5Sr_0.5TiO₃ thin films prepared on copper foils with La₂O₃ buffer layers. Applied Surface Science 255: 8319-8323.

Garzela, C., Comini, E., Tempesti, E., Frigeri, C. & Sberveglieri, G. 2000. TiO₂ thin films by a novel sol-gel processing for gas sensor applications. Sensors and Actuators B(68): 189-196.

Hanani, N. 2005 The development of barium strontium titanate ceramics bolometer as a distance sensor. Master Thesis. Universiti Kebangsaan Malaysia, Bangi (unpublished).

Stamate, M.D. 2000. Dielectric properties of TiO₂ thin films deposited by a DC magnetron sputtering system. Thin Solid Films 372: 246-249.

Tsuzuki, A., Kato, K., Kusumoto, K. & Torh, Y. 1998. Preparation and characterization of Ba1-_xS_rxTiO₃ films by sol-gel processing. J. Mater. Sci. 33: 3055-3058

Wu, D., Li, A., Ling, H., Yin, X., Ge, C., Wang, M & Ming, N. 2000. Preparation of (Ba_0.5Sr_0.5TiO₃ thin films by sol-gel method with rapid thermal anneaing. J. Appl. Surface Sci. 165: 309-314.

*Corresponding author; email: baayah@ukm.my