Sains Malaysiana 43(6)(2014):
833–842
Characteristics
of Nanostructured CaxZn(1-x)Al2O4
Thin Films Prepared by Sol-Gel Method
for GPS Patch
Antennas
(Ciri Filem
Nipis CaxZn(1-x)Al2O4 Berstruktur Nano yang Dihasilkan Melalui Kaedah
Sol-Gel untuk
GPS Tampalan Antena)
WAN NASARUDIN WAN
JALAL1, HUDA
ABDULLAH1*, MOHD
SYAFIQ
ZULFAKAR1, SAHBUDIN
SHAARI2, MOHAMMAD
THARIQUL
ISLAM3& BADARIAH BAIS1
1Department of Electrical, Electronic
and System Engineering, Faculty of Engineering and Built Environment,
Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia
2Institute
of Microengineering and Nanoelectronics (IMEN), Universiti Kebangsaan
Malaysia, 43600 Bangi, Selangor, Malaysia
3The Institute of Space Science (ANGKASA),
Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia
Diserahkan: 28 Mac 2013/Diterima:
2 Februari 2014
ABSTRACT
CaxZn(1-x)Al2O4
thin films (x = 0.00; 0.05; 0.10; 0.15 and 0.20) were
prepared by sol-gel method with the substitution of Zn2+ by
Ca2+ in the framework of ZnAl2O4.
The effect of Ca addition on the structure and morphology of CaZnAl2O4 thin
films was investigated by x-ray diffraction (XRD),
field-emission scanning electron microscope (FESEM),
energy-dispersive x-ray spectroscopy (EDX), ultra-violet visible (UV-Vis)
and atomic force microscope (AFM). The XRD patterns
showed the characteristic peaks of face-centred cubic (fcc) ZnAl2O4 and
CaZnAl2O4. The addition of Ca increased
the crystallite size from 8.9 to 30.2 nm. The bandgap of CaxZn(1-x)Al2O4
thin film was found in the range of 3.40 to 3.84 eV. SEM micrograph
shows the morphology of all thin films is sphere-like, with the
grain size increased from 33 to 123 nm. The AFM images show the roughness
of surface morphology increased. The substitution of Zn2+ by
Ca2+ increased the crystallite size, grain size and surface
roughness which evidently increased the density (4.59 to 4.64 g/cm3)
and dielectric constant (8.48 to 9.54). The composition of
CaxZn(1-x)Al2O4 is
considered as suitable material for GPS patch antennas.
Keywords: Band gap; Ca-ZnAl2O4; GPS patch antena; nanostructures
ABSTRAK
Filem nipis CaxZn(1-x)Al2O4(x
= 0.00; 0.05; 0.10; 0.15 dan 0.20) telah dihasilkan dengan kaedah
sol-gel iaitu menggantikan Zn2+ dengan Ca2+ di
dalam bahan utama ZnAl2O4. Kesan
terhadap penambahan Ca pada struktur dan morfologi filem nipis CaZnAl2O4
telah dianalisis dengan menggunakan pembelauan sinar-x
(XRD),
mikroskopi imbasan pancaran medan elektron (FESEM),
x-ray serakan tenaga spektroskopi (EDX), cahaya nampak ultra lembayung
(UV-Vis) dan mikroskopi daya atomik (AFM).
Corak pembelauan XRD menunjukkan ciri-ciri puncak berpusat
muka padu pada bahan ZnAl2O4 dan
CaZnAl2O4. Penambahan Ca telah meningkatkan
saiz kristal daripada 8.9 kepada 30.2 nm. Jalur tenaga bagi filem
nipis CaxZn(1-x)Al2O4 ialah
antara 3.40 hingga 3.84 eV. Graf mikro SEM menunjukkan morfologi bagi
kesemua filem nipis adalah berbentuk butiran dengan saiz butiran
meningkat daripada 33 kepada 123 nm. Imej AFM menunjukkan berlakunya peningkatan
pada permukaan morfologi CaxZn(1-x)Al2O4.
Penggantian Zn2+ dengan
Ca2+ telah meningkatkan saiz butiran dan peningkatan
kekasaran permukaan yang seterusnya memberi kesan terhadap ketumpatan
bahan (4.59 kepada 4.64 g/cm3) dan pemalar dielektrik (8.48
kepada 9.54). Komposisi CaxZn(1-x)Al2O4 dianggap
sebagai bahan yang sesuai untuk penghasilan GPS tampalan
antena.
Kata kunci: Ca-ZnAl2O4;
GPS tampalan antena;
jalurtenaga; strukturnano
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*Pengarang untuk
surat-menyurat; email: huda@vlsi.eng.ukm.edu.my
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