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Struktur
dan Sifat Optik Filem Nipis Nanozarah ZnO Terdop Ga
(Structural and Optical Properties of Ga-doped ZnO Nanoparticle Thin Films)
Diserahkan:
13 Jun 2012/Diterima: 11 Jun 2013
ABSTRAK
Filem nipis ZnO terdop Ga (ZnO:Ga)
disediakan menggunakan teknik sol-gel dan salutan berputar. Ga
didopkan kepada ZnO dengan peratusan berat (wt. %) yang berbeza iaitu 0, 2, 4,
6 dan 8 wt. %. Kesan pengedopan Ga ke atas struktur
dan sifat optik filem nipis ZnO dikaji. Pencirian struktur filem nipis
ini dilakukan menggunakan kaedah pembelauan sinar-X (XRD), mikroskop imbasan
elektron pancaran medan (FESEM) dan mikroskop daya
atom (AFM). Pencirian sifat optik filem nipis pula dilakukan menggunakan
spektroskopi ultraungu cahaya nampak (UV-VIS) dan fotoluminesen (PL). Ujian XRD mengesahkan kesemua sampel berstruktur
wurtzit. Saiz kristalit ZnO mengecil dengan
peningkatan peratusan berat Ga seterusnya mengurangkan kekasaran permukaan
filem. Pengedopan Ga menunjukkan peratus transmisi
cahaya pada panjang gelombang 300 - 380 nm bertambah berbanding filem nipis ZnO
tanpa dop. Nilai jurang tenaga optik, Eg dan keamatan PL filem nipis ZnO
meningkat apabila pengedopan Ga dilakukan. Hasil
kajian ini menunjukkan saiz kristalit yang lebih kecil memberi kesan ke atas
sifat optik sampel pada peratus pengedopan Ga 0-6%. Pada
peratus pengedopan Ga yang lebih tinggi, kesan transformasi struktur menjadi
lebih dominan dalam mempengaruhi nilai Eg.
Kata kunci: Fotoluminesen; jurang tenaga optik; sol-gel
ABSTRACT
Ga-doped zinc oxide (ZnO:Ga) thin films
were prepared by using sol-gel spin coating method. Different weight
percentage, wt. % (0, 2, 4, 6 and 8 wt. %) were doped into ZnO thin films. The
effects of Ga dopant on structural and optical properties of these films were
investigated. The structural properties of these thin films were studied by
X-ray diffractometer (XRD), field emission scanning electron
microscope (FESEM)
and atomic force microscope (AFM). The optical properties were examined by
ultraviolet visible spectroscopy (UV-VIS) and photoluminescence (PL) spectroscopy. XRD measurement
indicates that all the samples displayed wurtzite structure. The crystallite
size of the films reduced with the increase of Ga concentrations and the
surface roughness remarkably decreased. Ga-doping has clearly increased the
light transmission percentage for wavelength in the range of 300 - 380 nm as
compared to un-doped ZnO film. The optical band gap, Eg and the PL intensity of the films
increased with the Ga-doping. The experimental results showed that, smaller
crystallite size has an effect on the optical properties of the samples at 0-6%
of Ga-doping. Structural transformation has more dominant influence to the Eg value
at higher percentage of Ga-doping.
Keywords: Optical band gap; photoluminescence;
sol-gel
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*Pengarang untuk surat-menyurat; email: rozida@ukm.my
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