Sains Malaysiana 43(12)(2014): 1943–1949

Growth of Gallium Nitride Thin Film with the Aid of Polymethyl Methacrylate

(Pertumbuhan Filem Nipis Galium Nitrida dengan Bantuan Polimetil Metakrilat)

C.Y. FONG*, S.S. NG, F.K. YAM, H. ABU HASSAN & Z. HASSAN

Nano-optoelectronics Research and Technology Laboratory, School of Physics,

Universiti Sains Malaysia, 11800 Penang, Pulau Pinang, Malaysia

Received: 25 March 2013/Accepted: 17 April 2014

ABSTRACT

Wurtzite structure gallium nitride (GaN) thin film was grown on a c-plane sapphire (0001) substrate through spin coating method followed by nitridation process. Readily available and cheap gallium (III) nitrate hydrate (Ga(NO₃)3·xH₂O) powder was used as the gallium source. Besides that, ethanol-based precursor solution which has better wetting properties and fast evaporation rate was prepared. In addition, a thin layer of polymethyl methacrylate was introduced as a bonding adhesive layer for the growth of the GaN thin film. X-ray diffraction results indicated that the deposited film consists of nanocrystallite GaN with hexagonal wurtzite structure. Field-emission scanning electron microscopy showed the morphologies of the small and well-defined spherical grains that coated on the substrate. The synthesized GaN thin film demonstrated a pronounced and broad exciton peak at 380 nm in Photoluminescence spectrum. Raman scattering measurements showed two features that correspond to the E2 (high) and A1 (LO) phonon modes of the hexagonal GaN.

Keywords: Nitridation; Sapphire; spin coating

ABSTRAK

Struktur Wurtzite filem nipis galium nitrida (GaN) telah ditumbuhkan di atas substrat c-satah nilam (0001) melalui kaedah salutan putaran diikuti oleh proses penitridaan. Serbuk Galium (III) nitrat hidrat (Ga(NO₃)3·xH₂O) yang mudah didapati dan murah telah digunakan sebagai sumber galium. Selain itu, etanol berasaskan pelopor penyelesaian yang mempunyai sifat pembasahan yang lebih baik dan kadar penyejatan yang cepat telah disediakan. Di samping itu, lapisan nipis polimetil metakrilat telah diperkenalkan sebagai lapisan pelekat ikatan untuk pertumbuhan filem nipis GaN. Keputusan pembelauan sinar-X menunjukkan bahawa filem terdiri daripada nano kristalit GaN dengan struktur wurtzite heksagon. Pemancaran medan mikroskop elektron imbasan menunjukkan morfologi bijirin kecil dan berbentuk sfera telah ditumbuhkan pada substrat. Filem GaN nipis menunjukkan satu exciton puncak yang ketara dan luas pada 380 nm dalam keputusan fotoluminesen. Ukuran serakan Raman menunjukkan dua ciri-ciri yang sesuai dengan E2 (High) dan A1 (LO) fonon mod GaN heksagon.

Kata kunci: Nilam; penitridaan; salutan berputar

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*Corresponding author; email: louisfong331@hotmail.com