Sains Malaysiana 40(3)(2011): 245–250

ZnO:Sn Deposition by Sol-gel Method:Effect of Annealing on the Structural, Morphology and Optical Properties

(Pemendapan ZnO:Sn melalui Kaedah Sol-gel: Pengaruh Pertumbuhan Terhadap Struktur, Morfologi dan Sifat Optik)

H. Abdullah^*,1, S. Selmani¹, M.N. Norazia¹, P.S. Menon², S. Shaari^1,2 & C.F. Dee²

¹Department of Electric, Electronic & System, Faculty of Engineering

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

²Institute of Microengineering and Nanoelectronics (IMEN)

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

Received: 21 July 2010 / Accepted: 3 September 2010

ABSTRACT

Sn doped zinc oxide polycrystalline thin films were prepared by sol-gel process. The sol was prepared from zinc acetate dehydrate and tin chloride were used. 2-methoxyethanol and monoethanolamine were used as the solvent and stabilizer, respectively. The quantity of tin in the sol was 0, 15 and 25 at.% Sn with annealing temperature 400, 500 and 600°C. Structural investigation including surface morphology and microstructure was carried out by X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). The films give a hexagonal wurtzite structure with diffraction peaks at (100), (002) and (101). Changes in particle size with an increase in annealing temperature were observed in the SEM micrograph. The optical properties were determined by photoluminescence (PL) and UV-Visible (UV-VIS-NIR) spectrometer. The band gaps increased (2.78 eV to 4.10 eV) as the concentration of Sn was increased and the increasing of annealing temperature. Annealing temperature plays a key role in the formation of defects which is strongly related to the nonradiative recombination centers. The increment of the band gap is acceptable as a requirement for good anti-reflecting coating element. Therefore, these films can be applied on silicon solar cells.

Keywords: Annealing temperature; anti-reflecting coating; sol-gel

ABSTRAK

Filem nipis zink oksida didop Sn telah disediakan melalui proses sol-gel. Sol telah dibuat daripada zink asetat nyahhidrat dan timah klorida. 2-methoxyethanol dan monoethanolamine masing-masing telah digunakan sebagai pelarut dan penstabil. Kuantiti timah dalam sol adalah 0,15 dan 25 at.% Sn dengan suhu penyepuhlindapan 400, 500 dan 600°C. Struktur termasuk morfologi permukaan dan mikrostruktur telah dikaji dengan pengukuran pembelauan sinar-X (XRD) dan mikroskop elektron imbasan (SEM). Filem menunjukkan struktur wurzit bersegi enam dengan puncak belauan pada kedudukan (10), (002) dan (101). SEM menunjukkan perubahan dalam saiz zarah dengan satu peningkatan dalam suhu penyepuhlindapan telah dicerap. Sifat optik telah ditentukan oleh fotoluminesens dan analisis spektrometer UV-Vis-NIR (UV-VIS). Nilai jurang jalur yang diperolehi bertambah (2.78 eV to 4.10 eV) bagi peningkatan Sn dan juga dengan penambahan suhu penyepuhlindapan. Dicadangkan suhu penyepuhlindapan memainkan peranan penting dalam pembentukan kecacatan, yang berkait rapat untuk penggabungan semula pusat-pusat yang tiada radiasi. Penambahan peningkatan jurang jalur diterima sebagai lapisan anti pantulan yang baik. Oleh sebab itu, filem ini boleh diterapkan pada sel suria silikon.

Kata kunci: Lapisan anti-pantulan; sol-gel; suhu penyepuhlindapan

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*Corresponding author; email: huda@vlsi.eng.ukm.my