Hydrogenated microcrystalline silicon ͑ c-Si:H͒ thin-film solar cells were prepared at high rates by very high frequency plasma-enhanced chemical vapor deposition under high working pressure. The influence of deposition parameters on the deposition rate ͑R D ͒ and the solar cell performance were comprehensively studied in this paper, as well as the structural, optical, and electrical properties of the resulting solar cells. Reactor-geometry adjustment was done to achieve a stable and homogeneous discharge under high pressure. Optimum solar cells are always found close to the transition from microcrystalline to amorphous growth, with a crystallinity of about 60%. At constant silane concentration, an increase in the discharge power did hardly increase the deposition rate, but did increase the crystallinity of the solar cells. This results in a shift of the c-Si:H/a-Si:H transition to higher silane concentration, and therefore leads to a higher R D for the optimum cells. On the other hand, an increase in the total flow rate at constant silane concentration did lead to a higher R D , but lower crystallinity. With this shift of the c-Si:H/a-Si:H transition at higher flow rates, the R D for the optimum cells decreased. A remarkable structure development along the growth axis was found in the solar cells deposited at high rates by a "depth profile" method, but this does not cause a deterioration of the solar cell performance apart from a poorer blue-light response. As a result, a c-Si:H single-junction p-i-n solar cell with a high efficiency of 9.8% was deposited at a R D of 1.1 nm/s.

We present a stand-alone integrated solar water-splitting device with an active area of 64 cm2 and a long-term stable operation. The modular setup of the device provides a versatile tool to integrate and evaluate various combinations of photoelectrodes and catalysts.

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The Green's function of the relativistic Aharonov-Bohm-Coulomb system is given by the Feynman-Kac formula. The earlier treatment is based on the multiple-valued transformation of Levi-Civitá. The method used in this contribution involves only the explicit form of a simple Green's function and an explicit path integral is avoided.

Hot-wire chemical vapor deposition (HWCVD) was utilized to develop a fast and high quality a-Si:H thin film fabrication method for poly-Si/SiOx carrier selective passivating contacts targeting at n-type passivated emitter rear totally diffused crystalline silicon solar cells. The microstructure and hydrogen content of the a-Si:H thin films were analyzed by Fourier-transform infrared spectroscopy in order to understand the influence of film properties on passivation and conductivity. Dense layers were found to be beneficial for good passivation. On the other hand, blistering appeared as a-Si:H layers became more and more dense. However, by adjusting the SiH4 flow rate and the substrate heater temperature, blistering of a-Si:H could be avoided. A suitable process window was found and firing-stable implied open circuit voltage (iVoc) of up to 738 mV was achieved. In addition to high iVoc, a low contact resistivity of 0.034 Ω cm2 was also achieved. The deposition rate of the a-Si:H layers was 7 Å/s by using HWCVD, which is one order of magnitude higher than the deposition rate reported using other deposition methods.