Sains Malaysiana 41(3)(2012): 339–344

Effect of Annealing Temperature of Sol-Gel TiO2 Buffer Layer on Microstructure

and Electrical Properties of Ba_0.6Sr_0.4TiO₃ Films

(Kesan Suhu Sepuhlindap Lapisan Penimbal TiO₂ Sol-Gel Terhadap Mikrostruktur

dan Sifat Elektrik Filem Ba_0.6Sr_0.4TiO₃)

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

School of Applied Physics, Faculty of Science and Technology

Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor D.E. Malaysia

Diserahkan: 9 Mac 2011 / Diterima: 19 September 2011

ABSTRACT

Ba_0.6Sr_0.4TiO₃ (BST) thin films were prepared on TiO2 buffer layers. The buffer layers were prepared using sol-gel method, followed by annealing process at different temperature from 300 to 55^oC with 50^oC interval for 30 min in air. The  microstructure and electrical properties of BST were then investigated. Increasing the annealing temperature increased. The buffer layer thickness BST films prepared on thicker buffer layer showed improved crystallinity. Without the buffer layer, BST crystallization cannot occur at 700 ^oC. However with buffer layer, 700 ^oC is sufficient for the process to occur. The BST grain size increased with the buffer grains increment. The existence of TiO₂ buffer layer increased the current density. The dielectric constant, εr´ and dielectric loss were not affected much by the buffer layer except at frequency around 1 kHz that showed an increment in the εr’ value with the increment of the annealing temperature.

Keywords: Annealing; buffer layer; electrical properties; sol-gel

ABSTRAK

Filem nipis Ba_0.6Sr_0.4TiO₃ (BST) telah disediakan di atas lapisan penimbal TiO₂. Lapisan penimbal disediakan dengan kaedah sol-gel, diikuti dengan proses sepuh lindap pada suhu yang berbeza daripada 300 hingga 550^oC dengan sela 50^oC selama 30 min dalam udara biasa. Mikrostruktur dan sifat elektrik BST telah dikaji. Kenaikan suhu sepuh lindap meningkatkan ketebalan lapisan penimbal. Filem BST yang disediakan di atas lapisan penimbal yang lebih tebal mempunyai penghabluran yang lebih sempurna. Tanpa lapisan penimbal, penghabluran BST tidak boleh berlaku pada suhu 700 ^oC, namun begitu dengan adanya lapisan penimbal, 700 ^oC sudah mencukupi untuk membenarkan proses penghabluran berlaku. Saiz butiran BST meningkat dengan peningkatan butiran penimbal. Kewujudan lapisan penimbal TiO₂ jugameningkatkan ketumpatan arus. Namun pemalar dielektrik, εr´ dan kehilangan dielektrik tidak begitu dipengaruhi oleh lapisan penimbal kecuali pada frekuensi lebih kurang 1 kHz yang menunjukkan penambahan εr’ dengan peningkatan suhu sepuh lindap.

Kata kunci: Lapisan penimbal; sepuh lindap; sifat elektrik; sol-gel

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*Pengarang untuk surat-menyurat; email: baayah@ukm.my