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Sains Malaysiana 46(10)(2017): 1951–1958 http://dx.doi.org/10.17576/jsm-2017-4610-34
Kesan Kuasa Frekuensi Radio terhadap Komposisi Ikatan Kimia Filem Nipis a-CNx sebagai
Pengesan Kelembapan (Influence
of RF Power on Chemical Bonding Composition on a-CNx Thin Films as Humidity Sensor) SITI AISYAH
ABD
AZIZ
& ROZIDAWATI AWANG* Pusat Pengajian
Fizik Gunaan,
Fakulti Sains dan
Teknologi, Universiti
Kebangsaan Malaysia, 43600 UKM Bangi, Selangor Darul Ehsan,
Malaysia Received: 30 June 2017/Accepted:
7 September 2017 ABSTRAK Filem nipis a-CNx mempunyai ikatan kimia C-N (sp3), C=N (sp2)
dan C≡N (sp1). Ikatan
C=N dan
C≡N mudah diputuskan oleh serangan hidrogen
semasa proses pemendapan
filem untuk membentuk
ikatan C-H dan
N-H. Pembentukan komponen sp2 grafit dalam filem
nipis a-CNx yang
disebabkan oleh
kewujudan atom nitrogen menyumbang
kepada penurunan
rintangan elektrik dan peningkatan kekonduksian elektrik. Ciri ini adalah penting
untuk aplikasi
filem nipis a-CNx sebagai pengesan kelembapan. Dalam kajian ini, filem nipis karbon
nitrida amorfus
(a-CNx) disediakan
di atas substrat
kuartza dan silikon
(111) menggunakan teknik
PECVD.
Sampel
disediakan pada kuasa frekuensi radio (RF) yang
berbeza iaitu pada
40, 50, 60, 70 dan 80 W dan
dikaji kesannya
ke atas komposisi
ikatan kimia
dan morfologi filem
serta keupayaannya
sebagai pengesan kelembapan. Puncak D (sp2C)
dan G (sp3C) yang jelas dicerap menggunakan
spektroskopi Raman dalam
semua filem nipis
a-CNx yang
disediakan dengan
keamatan tertinggi didapati pada kuasa
RF 70 W. Mikrokgraf daripada
mikroskop elektron
imbasan pancaran medan (FESEM) menunjukkan
morfologi permukaan
semua sampel mempunyai
struktur butiran
berbentuk seperti kobis bunga yang seragam. Spektroskopi fotoelektron sinar X (XPS)
mengesahkan kehadiran
ikatan C-C/C=C, C=N dan C≡N dalam filem nipis
a-CNx. Kesemua filem nipis
a-CNx yang
dihasilkan menunjukkan
tindak balas terhadap
kelembapan berbeza
dengan kepekaan antara 60-70%. Filem nipis a-CNx yang
disediakan pada
kuasa RF 70 W menunjukkan
kepekaan tertinggi
kesan daripada ketakteraturan karbon dan kandungan sp3C
yang lebih tinggi. Kata kunci:
Karbon nitrida;
PECVD;
saiz kelompok ABSTRACK The a-CNx thin
film has chemical bonding of C-N (sp3), C=N (sp2)
and C≡N (sp1).
C=N and C≡N bonds
are easily resolved by hydrogen attack during the film deposition
process to form C-H and N-H bonds. The formation of graphite
sp2 components
in the a-CNx thin
film caused by the presence of nitrogen atom contributes to
the reduction of the electrical resistance and enhances the
electrical conductivity. These features are essential for a-CNx thin
film application as a humidity sensor. In this study, amorphous
carbon nitride films (a-CNx) are deposited
on the quartz and silicon (111) substrate using PECVD techniques.
The samples were deposited at different RF power at 40, 50,
60, 70 and 80 W and analyzed their effects on film chemical
composition and films morphology as well as their ability as
humidity sensor. D (sp2C)
peak and G (sp3C) peak are clearly observed using
Raman spectroscopy in all a-CNx thin
films with the highest intensity obtained at RF 70
W. Films micrograph observed by field emission scanning electron
microscopy (FESEM)
show that surface morphology of all samples have a uniform structural
shape of cauliflower. X-ray photoelectron spectroscopy (XPS)
confirmed the presence of C-C/C=C, C=N and C≡N bonds
in the a-CNx thin
film. All the a-CNx thin
films showed a response to different humidity with sensitivity
between 60-70%. The a-CNx thin
film deposited at RF 70 W power indicates the highest sensitivity
due to carbon disorder and higher sp3C
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A: Physical 168(1): 10-13. *Corresponding author;
email: rozida@ukm.edu.my
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