Sains Malaysiana 38(2): 215-218(2009)

Physical Properties of Cuprous Oxide Thin Films Grown on n-Si

Substrate by Sol-Gel Spin Coating

(Sifat Fizikal Filem Nipis Kuprus Oksida Yang Di Mendapkan Di atas

Substrat N-Si Melalui Kaedah Salutan Berputar Sol-Gel)

D.S. CHE HALIN, I.A. TALIB_, A.R. DAUD & M.A.A. HAMID

School of Applied Physics, Universiti Kebangsaan Malaysia

43600 Bangi, Selangor, Malaysia

Received:  12 June 2008 / Accepted: 30 June 2008

ABSTRACT

Cu₂O films were grown on n-Si substrates via the sol-gel spin-coating method. The films were annealed under 5% H₂ + 95% N₂ atmosphere at 350°C, 450°C and 550°C.  Diffractogram obtained by the grazing angle x-ray diffractometry showed that the crystallinity of the films increased with increasing annealing temperature. Scanning electron microscopy micrographs revealed that the Cu₂O films contain grains of irregular size indicating that the film growth followed the Volmer-Weber growth mode. The micrographs showed the size evolved from irregular shapes with average size of 100 nm at 350°C into rectangular shapes with average size of 200 nm at 550°C. Optical reflectance for 450°C and 550°C film increased gradually at wavelength 480 nm. Higher reflectance for the 450 °C film might be due to better coverage of the film. It also showed that optical absorption occured at wavelength below 480 nm.

Keywords: crystallinity; cuprous oxide; sol-gel; Volmer-Weber growth

ABSTRAK

Filem Cu₂O dienapkan ke atas n-Si menggunakan kaedah sol-gel salutan berputar. Filem disepuh lindap di dalam atmosfera 5% H₂ + 95% N₂ pada suhu 350°C, 450°C dan 550 °C. Belauan sinar-X penujuan gesel menunjukkan kristaliniti yang meningkat dengan peningkatan suhu sepuh lindap. Mikrograf mikroskopi elektron imbasan memaparkan filem Cu₂O mengandungi saiz butiran yang tidak sekata yang menunjukkan pertumbuhan filem berdasarkan model pertumbuhan Volmer-Weber. Mikrograf menunjukkan pertumbuhan saiz dan butiran daripada butiran yang tidak sekata dengan purata saiz 100 nm pada suhu 350°C kepada butiran berbentuk segiempat dengan purata saiz 200 nm pada suhu 550 °C. Pantulan optik bagi filem yang disepuh lindap pada suhu 450°C dan 550°C meningkat secara beransur-ansur pada jarak gelombang 480 nm. Filem pada suhu sepuh lindap 450°C mempunyai peratus pantulan yang lebih tinggi mungkin disebabkan oleh liputan filem yang baik.  Ini menunjukkan penyerapan berlaku di bawah jarak gelombang 480 nm.

Kata kunci: Kristaliniti; kuprus oksida; pertumbuhan Volmer-Weber; sol-gel  

REFERENCES

Armelao, L., Barreca, D., Bertapelle, M., Bottaro, G., Sada, C. & Tondello, E. 2003. A Sol-Gel Approach To Nanophasic Copper Oxide Thin Films. Thin Solid Films 442: 48-52.

Nair, M.T.S., Guerrero, L., Arenas, O.L. & Nair P.K. 1999. Chemically Deposited Copper Oxide Thin Films: Structural, Optical And Electrical Characteristics. Applied Surface Science 150: 143-151.

Nikesh, V.V., Mandale, A.B., Patil, K.R., &  Mahamuni, S. 2005. X-Ray Photoelectron Spectroscopic Investigations Of Cu₂O Nanoparticles. Materials Research Bulletin 40: 694–700.

Ohring, M. 1992. The Materials Science Of Thin Films. Boston: Mass. Academic Press.

Omote, K. & Harada, J. 2000.  JCPDS-International Center For Diffraction Data, Advances In X-Ray Analysis 43: 192.

Oral, A.Y., Mensur, E., Aslan, M.H. & Basaran, E. 2004.  The Preparation Of Copper (II) Oxide Thin Films and The Study Of Their Microstructures and Optical Properties.  Materials Chemistry And Physics 83: 140-144.