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Pretreatment of the indium tin oxide (ITO) surface is generally adopted to improve the charge injection and device performance in the fabrication of organic light-emitting diodes (OLEDs). For the common approaches of surface treatment, such as oxygen plasma treatment, self-assembled monolayer (SAM) adsorption, and the PEDOT:PSS coating, different effects on the device lifetime were observed. A distinctly different driving voltage change with device operation time was obtained and was correlated with the device lifetime. The fast increase in driving voltage for devices based on oxygen-plasma-treated ITO is attributed to the work function change as a result of the change in the composition of the interface with device operation, whereas a rather stable work function for SAM-modified ITO is suggested due to the permanent dipoles associated with the monolayer and the protecting effect of the covalently bound monolayer on the surface composition.

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Finite Si atom diffusion induced size limitation of self-assembled Si quantum dots (Si-QDs) in silicon-rich silicon carbide (SiC) is demonstrated. After annealing, the Si-QDs with a size of 3 ± 1 nm are precipitated in the matrix of SiC 0.51 deposited by low-temperature plasma-enhanced chemical vapor deposition with Argon-diluted silane and methane mixture. The amorphous-Si dependent Raman scattering peak at ∼470 cm −1 is narrowing with increasing temperature, and the Si-CH 3 rocking-mode absorption line is shifted by dehydrogenation after high-temperature treatment. The self-assembled Si-QDs in SiC 0.51 with a volume density of 4.4 × 10 18 cm −3 transfer from amorphous to crystalline phase by increasing annealing temperature from 850 • C to 1050 • C. The calculated Si atom diffusion coefficient of 3-4 × 10 −4 nm 2 s −1 in Si-rich SiC 0.51 is 7 orders of magnitude larger than that in pure SiC, which coincides with the linear extrapolation from pure Si and SiC and reveals nonlinear proportionality with C/Si composition ratio and Si-QD size.