Investigation of Charge Compensation in Indium-Doped Tin Dioxide by Hydrogen Insertion Via Annealing under Humid Conditions

The behavior of hydrogen (H) as an impurity in indium (In)-doped tin dioxide (SnO2) was investigated by mass spectrometry analyses, with the aim of understanding the charge compensation mechanism in SnO2. The H-concentration of the In-doped SnO2 films increased to (1–2) × 1019 cm−3 by annealing in a humid atmosphere (WET annealing). The electron concentration in the films also increased after WET annealing but was two orders of magnitude less than their H-concentrations. A self-compensation mechanism, based on the assumption that H sits at substitutional sites, is proposed to explain the mismatch between the electron- and H-concentrations.