STUDY OF ELECTRONIC STRUCTURE OF TIN-DOPED In₂O₃ (ITO) FILM DEPOSITED ON GLASS 

Ali Hassanzadeh, Mohammad Hossein Habibi,* and Asghar Zeini-Isfahani
Department of Chemistry, University of Isfahan, 81745, Isfahan, Iran

Abstract

Electronic properties of lowly tin doped In₂O₃ (ITO) electrode with nanoscale particles (ca. 36 nm) prepared by electron-beam evaporation on glass substrate in contact with 0.1 mol dm^-3 H₂SO₄ solution under visible light was investigated by means of linear sweep voltammetry and electrochemical impedance spectroscopy techniques. Differential capacitance results showed that in the high frequency region of EIS data, ITO and impurity element oxides may develops a p-n junction (Esaki tunnel diode) with low charge carrier concentration (N_D = 2.07×10⁹ cm^-3). In this EIS data region, a reverse semicircle with a negative resistance was appeared. In contrast, in the low frequency region of EIS data, these semiconductors were converted into only n-type one. The flat-band potential of ITO film at low frequency region as determined from capacitance measurements was found to be around -0.0344 volt vs. SCE. Also, from the slope of linear portion of Mott-Schottky plot, charge carrier concentration was calculated to be about N_D = 7.1501×10²¹ cm^-3.

Key words: EIS, Mott-Schottky plot, electronic structure, electron beam evaporation, ITO