Optical absorption behaviour of vanadium pentoxide thin films

✍ Scribed by C. V. Ramana; O. Mahammad Hussain

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 172 KB
• Volume: 7
• Category: Article
• ISSN: 1616-301X
• DOI: 10.1002/(sici)1099-0712(199709)7:5<225::aid-amo309>3.0.co;2-r

✦ Synopsis

Thin ®lms of vanadium pentoxide have been prepared by the electron beam evaporation technique over a wide range of substrate temperatures. Spectrophotometric investigations have been made on these ®lms in the wavelength range 350±1500 nm to determine the nature of the optically induced transition and the optical band gap. A better ®t for the direct forbidden transition than for the indirect allowed transition is observed in all the ®lms. The optical band gap is found to decrease with increasing substrate temperature and the subsequent appearance of a broadband absorption at about 1000 nm is attributed to the oxygen vacancies in the ®lms. The eect of heat treatment in vacuum and oxygen ambient on the optical properties of these ®lms is also reported. *