A study of the characteristics of indium tin oxide after chlorine electro-chemical treatment

作者：Kim Moonsoo; Kim Jongmin; Cho Jaehee; Kim Hyunwoo; Lee Nayoung; Choi Byoungdeog^*

来源：Materials Research Bulletin, 2016, 82: 115-121.

DOI：10.1016/j.materresbull.2016.03.008

• Metals (indium tin oxide)
• Chemical synthesis (chlorination)
• Electrical properties (electro-negativity)
• Surface properties (surface dipole)
• Fermi surface (vacuum level shift)

In this work, we investigate the influence of a chlorine-based electro-chemical surface treatment on the characteristics of indium tin oxide (ITO) including the work function, chemical composition, and phase transition. The treated ITOs were characterized using X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), 4-point probe measurements, and grazing incidence X-ray diffraction (GI-XRD).
We confirmed a change of the chemical composition in the near-surface region of the ITO and the formation of indium-chlorine (In-Cl) bonds and surface dipoles (via XPS). In particular, the change of the electro-static potential in the outer surface was caused by chlorination.
Due to the vacuum-level shift after the electro-chemical treatment in a dilute hydrochloric acid, the ITO work function was increased by.0.43 eV (via UPS); furthermore, the electro-negativity of the chlorine anions attracted electrons to emit them from the hole transport layer (HTL) to the ITO anodes, resulting in an increase of the hole-injection efficiency.

• 出版日期2016-10