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Low-pressure thermogravimetry; vapour pressure; Langmuir equation; partial pressure; precursor; metalorganic chemical vapour deposition.

A method for the estimation of vapour pressure and partial pressure of subliming compounds under reduced pressure, using rising temperature thermogravimetry, is described in this paper. The method is based on our recently developed procedure to estimate the vapour pressure from ambient pressure thermogravimetric data using Langmuir equation. Using benzoic acid as the calibration standard, vapour pressure–temperature curves are calculated at 80, 160 and 1000 mbar for salicylic acid and vanadyl bis-2,4-pentanedionate, a precursor used for chemical vapour deposition of vanadium oxides. Using a modification of the Langmuir equation, the partial pressure of these materials at different total pressures is also determined as a function of temperature. Such data can be useful for the deposition of multi-metal oxide thin films or doped thin films by chemical vapour deposition (CVD).

G V Kunte¹ Ujwala Ail² P K Ajikumar² A K Tyagi² S A Shivashankar¹ A M Umarji¹

1. Materials Research Centre, Indian Institute of Science, Bangalore 560 012, India
2. Materials Science Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, India

Published

December 2011

Manuscript received

1 August 2009