Substrate temperature influenced structural, electrical and optical properties of dc magnetron sputtered MoO 3 films

• Published in: Applied surface science Vol. 256; no. 10; pp. 3133 - 3137
• Main Authors: Uthanna, S., Nirupama, V., Pierson, J.F.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.2010
• Subjects: Electrical and optical properties; Molybdenum oxide; Reactive sputtering; Structure; 68.35 B; Electrical and optical properties; 64.70 F; 81.40 Tv; 81.15 Cd; Molybdenum oxide; Reactive sputtering; Structure
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2009.11.086

Molybdenum oxide (MoO 3) films were deposited on glass and (1 1 1) silicon substrates by sputtering of metallic molybdenum target in an oxygen partial pressure of 2 × 10 −4 mbar and different substrate temperatures in the range 303–623 K using dc magnetron sputtering technique. X-ray photoelectron spectrum of the films formed at 303 K showed asymmetric Mo 3d 5/2 and Mo 3d 3/2 peaks due to the presence of mixed oxidation states of Mo 5+ and Mo 6+ while those deposited at substrate temperatures ≥473 K were in Mo 6+ oxidation state of MoO 3. The films formed at substrate temperatures ≥473 K were polycrystalline in nature with orthorhombic α-phase MoO 3. Fourier transform infrared spectra of the films showed an absorption band at 1000 cm −1 correspond to the stretching vibration of Mo O, the characteristic of the α-MoO 3 phase. The electrical resistivity increased from 3.3 × 10 3 to 8.3 × 10 4 Ω cm with the increase of substrate temperature from 303 to 473 K respectively due to improvement in the crystallinity of the films. Optical band gap of the films increased from 3.03 to 3.22 eV with the increase of substrate temperature from 303 to 523 K.