In this work, a new type of short water vapor treatment of the interface between the p-and i-layer is presented. This novel treatment is performed under vacuum below 1 mbar for 5 min and considerably reduces the i-layer boron contamination in amorphous silicon (a-Si:H) p-i-n solar cells prepared in single-chamber reactors. A significant advantage is that the substrate with the p-layer can remain loaded in the reactor during this oxidation treatment. The high effectiveness of this treatment in reducing the boron cross-contamination is directly supported by secondary ion mass spectroscopy measurements, by tracing the boron concentration depth profile across the p-i interface and by quantum efficiency measurements of the deposited cells. By applying this water vapor treatment, 0.3-mm-thick a-Si:H p-i-n solar cells of 1 cm with high initial conversion efficiencies of 10.1% are 2 deposited in a commercial large-area (35=45 cm ) single-chamber PECVD KAI reactor and can clearly compete with cells 2 deposited in multi-chamber systems. Light soaking of these cells for 1200 h at 50 8C leads to stabilized efficiencies of 8.2%. The relative typical efficiency degradation of 20% of such 0.3-mm-thick single-junction cells demonstrates that this treatment does not affect the stability in a negative manner.

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Molecularly homogenous and hydrophobic surfaces play an important role in a number of technological applications such as tribology and protein/cellular adhesion. Self-assembled monolayers of dodecyl phosphates (DDPO 4 ) have previously been demonstrated to spontaneously form on titanium oxide, producing surfaces with excellent hydrophobic properties. In this paper, we report on the adsorption of DDPO 4 onto a transparent electronic material, indium tin oxide (ITO), under both open circuit and applied potential conditions. We have used two complementary surface characterization techniques: variable angle scanning ellipsometry and contact angle measurements to investigate the adsorption of DDPO 4 on an ITO surface. Under open circuit condition, both methods consistently confirmed the formation of DDPO 4 monolayers on the ITO surface. The presence of an electrical field increased the amount of DDPO 4 adsorbed on the ITO surface. An applied anodic electrical stimulus of 1800 mV resulted in an exponential loss of the monolayer as confirmed by X-ray photoelectron spectroscopy and electrochemical optical waveguide lightmode spectroscopy (EC-OWLS). This electrically stimulated selective adsorption/desorption of DDPO 4 opens up new ways to tailor the physico-chemical properties of surfaces.