Vaporization thermodynamics of In₂O₃ by Knudsen effusion mass spectrometry. The standard enthalpy of formation of In₂O(g)

Abstract

In 2 O 3 is one of the most important semiconductor oxides in modern electronics. Vacuum deposition methods are often used for the preparation of In 2 O 3based nanomaterials. Thus, vaporization thermodynamics is of key importance for process control and optimization. Since the literature data on the vapor composition and partial pressure values for In 2 O 3 are contradictory, vaporization thermodynamics of In 2 O 3 needs to be clarified. Methods: Vaporization behavior of In 2 O 3 was studied using the Knudsen effusion technique in the temperature range 1400-1610 K. Quartz effusion cells were employed. A magnet mass spectrometer with an ordinary focus and a sector-type analyzer was used. Heating of samples and molecular beam ionization were performed by electron impact. The operating ionizing electron energy was 75 eV. Results: A specially designed experiment allowed us to determine the individual mass spectrum of the In 2 O molecule and, thus, to interpret the mass spectrum of the vapor registered during In 2 O 3 vaporization. The composition of the equilibrium vapor was quantified and the partial pressures of the vapor species were determined. On