Applied Physics Letters · 2001 · 203 citations · 14 references
Natural SciencesMaterials SciencePhysicsElectronic MaterialsSemiconductor MaterialsSurface ScienceOxide SemiconductorsPlasma Surface TreatmentPlasma-surface InteractionsSemiconductor SurfacesSurface PhysicsX-ray Photoelectron SpectroscopyBand BendingBand GapFermi LevelSurface Band BendingSurface Electronic StructureTin OxidesValence BandWork Function
X-ray photoelectron spectroscopy (XPS) has been used to study the electronic structures of indium tin oxide (ITO) surfaces treated by O+, Ar+, and NHx+ plasmas. The XPS data show that there is a significant change in core level energies (In 3d5/2 O 1s, and Sn 3d5/2), in donor concentration (Sn4+), in valence band maximums (VBM), and in work functions on ITO surfaces being treated by O+ and NHx+ plasmas, compared with that of virgin and Ar+ plasma treated surfaces. Based on these experimental data, a surface band-bending theory is proposed. The theory explains that when Fermi energy of the plasma-treated surface is shifted towards the middle of the band gap: core levels will shift their energies to lower binding energies, VBM will bend upward, and work function will increase, as observed.
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Organic electroluminescent diodes
Chak Wah Tang, S. A. VanSlyke · Applied Physics Letters · 1987 · 14.3K citations
Natural Sciences, Materials Engineering, Materials Science +17
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