Sains Malaysiana 38(1): 85-89(2009)

Synthesis and Characterization of MoS₂ Films for Photoelectrochemical Cells

(Sintesis dan Pencirian Filem MoS₂  untuk Sel Fotoelektrokimia)

T. Joseph Sahaya Anand

Department of Materials Science, AIMST University

Jalan Semeling, 08100 Kedah, Malaysia

Received:  28 February 2008 / Accepted:  29 Mei 2008

ABSTRACT

Molybdenum disulfide (MoS₂) is a VI – VI compound semiconductor has hexagonal structure useful for high temperature lubricant. Polycrystalline films are electrodeposited cathodically on tin oxide (SnO₂) coated conducting glass substrates. The deposited films are characterized by various techniques includes the X-ray diffraction analysis, where the structure of the films is identified as hexagonal and the lattice parameters are a = b = 3.153 Å and c = 12.279 Å which are in good agreement with standard report values. From optical analysis, the bandgap value is calculated as 1.68 eV with indirect bandgap nature. From scanning electron micrographs, the surface appears to be comparatively granular with grains in irregularly shaped. The thickness of the MoS₂ films was calculated in the region 0.80 – 0.82 mm by using weight gain method.  From Mott-Schottky plots the films are found to be n-type and the semiconductor parameters of the film are derived. From the photoelectrochemical cell studies the fill factor, open circuit voltage, short circuit current and efficiency are calculated.

Keywords: Electrodeposition; MoS₂ thin film; Mott-Schottky plot; Photoelectrochemical cell; Semiconductor

ABSTRAK

Molibdenum disulfida (MoS₂) merupakan semikonduktor sebatian VI-VI yang mempunyai struktur heksagonal dan S₂ berguna sebagai pelincir suhu tinggi.  Filem polihablur dielektroendapkan secara katod di atas substrat kaca yang disalut timah oksida (SnO₂) yang mengkonduski. Filem yang diendapkan telah dicirikan dengan berbagai teknik termasuklah analisis pembelanan sinar-X dan struktur filem dikenal pasti sebagai heksogonad dengan parameter kekisi a = b = 3.153 Å dan C= 12.279 Å.  Ini adalah bertepatan dengan nilai piawai yang telah dilaporkan.  Daripada analisis optik, nilai jurang tenaga tak langsung yang dikira ialah 1.68 eV. Mikrograf elektron imbasan menunjukkan permukaan yang berbutiran dengan bentuk yang tidak sekata. Ketebalan filem MoS₂ yang diukur menggunakan kaedah tambah berat  adalah di antara 0.80 – 0.82 mm. Plot Mott-Schottky menunjukkan filem tersebut adalah semikonduktor jenis – n.  Daripada kajian faktor pengisian sel fotoelektrokimia, voltan litar terbuka, arus pintas dan kecekapan telah dikira.

Kata kunci:  Elektroendapan; filem nipis  MoS₂, Plot Mott-Schottky; sel fotoelektrokimia; semikonduktor

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