Sains Malaysiana 42(2)(2013): 193–196

Structural and Optical Properties of ZnO Thin Film Prepared by Oxidation of Zn Metal Powders

(Struktur and Ciri Optik Filem Nipis ZnO yang Disediakan oleh Kaedah Pengoksidaan

Serbuk Logam ZnO)

N.K. Hassan& M.R.Hashim*

Nano-optoelectronic Research Lab, School of Physics

Universiti Sains Malaysia, 11800 Penang, Malaysia

Received: 7 January 2012 / Accepted: 21 May 2012

ABSTRACT

High quality ZnO nanostructures have been fabricated at room temperature by a simple vacuum thermal evaporator from metallic Zn powders (99.999% purity) on a silicon (100) substrate. The Zn thin films were then transferred into a thermal tube furnace for oxidation at 700°C for different time durations. Time was found to be a critical factor in the synthesis. This was followed by characterization of their morphological, structural and optical properties. The morphology of the grown ZnO nanostructures exhibited several large grains, which increased gradually with increasing oxidation time. The crystallinity of the grown nanostructures was investigated using X-ray diffraction, revealing that the synthesized ZnO was in hexagonal wurtzite phase. The photoluminescence (PL) spectra of the fabricated ZnO nanostructures showed high intensity peak in the UV region due to near-band-edge (NBE) emission in which the structures oxidized for 30 min showing highest intensity.

Keywords: Photoluminescence; vacuum thermal evaporator; ZnO nanostructures

ABSTRAK

Struktur nano ZnO yang berkualiti tinggi telah difabrikasikan pada suhu bilik menggunakan teknik pengewap terma tervakum yang mudah daripada serbuk logam Zn (99.999% tulen) di atas substrat silikon (100). Filem nipis Zn kemudiannya dipindahkan ke dalam tiub relau pemanas untuk pengoksidaan pada suhu 700°C untuk masa yang berbeza. Masa pengoksidaan dikenal pasti sebagai sebagai faktor yang kritikal dalam sintesis. Ini diikuti oleh pencirian sifat-sifat permukaan, struktur dan optik. Permukaan struktur nano ZnO menunjukkan beberapa butiran yang besar, yang membesar apabila masa pengoksidaan ditingkatkan. Kehabluran struktur nano yang ditumbuh dikaji menggunakan pembelauan sinar-X, menunjukkan ZnO berada dalam fasa heksagonal wurtzit. Spektrum fotoluminesen (PL) struktur nano ZnO menunjukkan keamatan puncak yang tinggi di dalam rantau ultra-lembayung (UV) berpunca daripada pancaran daripada peralihan pinggir jalur dengan struktur teroksida pada 30 min menunjukkan pancaran paling tinggi keamatannya.

Kata kunci: Fotoluminesen; pengewap terma tervakum; struktur nano ZnO

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*Corresponding author; email: roslan@usm.my