The effects of Ar ion and Ar gas cluster ion beam (GCIB) sputtering processes on the core-level structure, valence band structure and work function of poly (3,4-ethylenedioxythiophene) polymerized with poly (4-styrenesulfonate) (PEDOT:PSS) and multi wall carbon nanotube (MWNT)/PEDOT:PSS films were characterized by photoemission spectroscopy and atomic forced microscopy. The depth profiles of X-ray photoemission and ultraviolet spectroscopy with Ar ion sputtering process confirmed that Ar ion sputtering process highly causes damage on the surface potential and valence band structure as well as core-level structure of PEDOT:PSS film. However, on the contrary to Ar ion sputtering, Ar GCIB sputtering process at each acceleration voltage did not induce any transition of chemical bonding state in PEDOT:PSS film and therefore, the atomic composition of Ar GCIB sputtered PEDOT:PSS film was also nearly same with that of as-dep. PEDOT:PSS film. Furthermore, the valence band structure and work function of organic composite films were not damaged by Ar GCIB sputtering process so that the energy band diagram between PEDOT:PSS and fluorine doped tin oxide films was clearly settled using valence band structure and work function of Ar GCIB sputtered PEDOT:PSS film.

In conventional semiconductor theory, greater doping decreases the electronic resistance of a semiconductor. For the bipolar resistance switching (BRS) phenomena in oxides, the same doping principle has been used commonly to explain the relationship between the density variation of oxygen vacancies (Vo¨) and the electronic resistance. We find that the Vo¨ density can change at a depth of ∼10 nm below the Pt electrodes in Pt/Nb:SrTiO3 cells, depending on the resistance state. Using electron energy loss spectroscopy and secondary ion mass spectrometry, we found that greater Vo¨ density underneath the electrode resulted in higher resistance, contrary to the conventional doping principle of semiconductors. To explain this seemingly anomalous experimental behavior, we provide quantitative explanations on the anomalous BRS behavior by simulating the mobile Vo¨ [J. S. Lee et al., Appl. Phys. Lett. 102, 253503 (2013)] near the Schottky barrier interface.

Damage profiles on Si (001) surface via argon gas cluster ion beam sputtering and mono-atomic argon ion beam sputtering were investigated using medium energy ion scattering. The surface thickness damaged by Ar cluster ion beam sputtering was approximately 10 nm for 20 keV, 6.4 nm for 10 keV, and 4.2 nm for 5 keV and the composition of the implanted Ar atoms was 0.2 at% for 20 keV and 0.1 at% for both 10 and 5 keV. The surface thickness damaged by Ar ion beam sputtering was approximately 5.3 nm for 1 keV, 8.5 nm for 2 keV, and 12 nm for 3 keV and the maximum Ar concentration of the implanted Ar atoms in the Si substrate was 5.5 at% for 1 keV, 5.8 at% for 2 keV, and 7.8 at% for 3 keV. The depth of the damaged layers after Ar ion sputtering on Si (001) is proportional to the in-depth distribution of the implanted primary Ar ions. The depth of the damaged layer after the Ar cluster ion beam sputtering did not depend on the implanted Ar atoms because the implanted Ar atoms are negligible. Understanding the details about the damage process via Ar cluster ion beam sputtering can be useful for the practical surface analysis.

We report on the degradation process by water vapor of hydrogenated amorphous silicon oxynitride (SiON:H) films deposited by plasma-enhanced chemical vapor deposition at low temperature. The stability of the films was investigated as a function of the oxygen content and deposition temperature. Degradation by defects such as pinholes was not observed with transmission electron microscopy. However, we observed that SiON:H film degrades by reacting with water vapor through only interstitial paths and nano-defects. To monitor the degradation process, the atomic composition, mass density, and fully oxidized thickness were measured by using high-resolution Rutherford backscattering spectroscopy and X-ray reflectometry. The film rapidly degraded above an oxygen composition of ~27 at%, below a deposition temperature of ~150 °C, and below an mass density of ~2.15 g/cm3. This trend can be explained by the extents of porosity and percolation channel based on the ring model of the network structure. In the case of a high oxygen composition or low temperature, the SiON:H film becomes more porous because the film consists of network channels of rings with a low energy barrier.

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