Very thin and stable thin-film silicon alloy triple junction solar cells by hot wire chemical vapor deposition

\u3cp\u3eWe present a silicon-based triple junction solar cell that requires a deposition time of less than 15 min for all photoactive layers. As a low-bandgap material, we used thin layers of hydrogenated amorphous silicon germanium with lower band gap than commonly used, which is possible due to the application of hot wire chemical vapor deposition. The triple junction cell shows an initial energy conversion efficiency exceeding 10%, and with a relative performance stability within 6%, the cell shows a high tolerance to light-induced degradation. With these results, we help to demonstrate that hot wire chemical vapor deposition is a viable deposition method for the fabrication of low-cost solar cells.\u3c/p\u3

Optical design of 4-terminal hybrid tandem modules combining thin-film top and c-Si bottom cells

\u3cp\u3eOptical simulations of 4-terminal tandem devices combining two different thin-film top cells with high-efficiency c-Si cells are presented. A methodology for evaluating the efficiency gain of tandem devices shows improvement of 19% IBC cells.\u3c/p\u3

Apparatus and process for producing thin films and devices

\u3cp\u3eA silicon nitride thin film formation apparatus is provided for stationary and moving substrates and a process for forming such films. The process provides high uniformity of film thickness and film properties as well as a high deposition rate. The film properties are adequate for application as an antireflection layer or passivation layer in solar cell devices or as dielectric layer in thin film transistors. The apparatus includes a number of metal filaments. In the space within the formation apparatus opposite to the substrate with respect to the filaments, a gas dosage system is arranged at a predetermined distance of the filaments. The film formation apparatus for stationary substrates also contains a shutter to control the starting and ending conditions for film formation and to control the film thickness.\u3c/p\u3

Synthesis of SnS/In2S3 core-shell nanoparticles

In this letter a new type of core–shell structure is presented. The core is made of tin-sulfide by colloidal route. The shell, made of indium-sulfide, by chemical bath deposition. These core–shell nanoparticles have been characterized by transmission electron microscope to study the size and the shape. High resolution TEM has allowed to determine the structure of the core and the shell. The chemical composition has been analyzed by energy-dispersive X-ray spectroscopy. In the end the optical absorption investigated by UV–vis changing the deposition time and temperature. Finally, the influence of these parameters on the band gap has been investigated

Compensation of self-absorption losses in luminescent solar concentrators by increasing luminophore concentration

\u3cp\u3eSelf-absorption in luminophores is considered a major obstacle on the way towards efficient luminescent solar concentrators (LSCs). It is commonly expected that upon increasing luminophore concentration in an LSC the absorption of the luminophores increases as well and therefore self-absorption losses will have higher impact on the performance of the device. In this work we construct a fully functioning liquid phase LSC where the luminophore concentration can be altered without changing other conditions in the experimental set-up. We step-wise enlarge the concentration of the luminophores Lumogen Red 305 and Lumogen Orange 240, while monitoring the electrical output and self-absorption effects. Contrary to common belief, self-absorption does not increasingly limit the performance of LSCs when the luminophore concentration increases.\u3c/p\u3

Probing periodic oscillations in a silane dusty plasma in a very high-frequency plasma enhanced chemical vapor deposition process

To estimate the dust formation time scale in a silane–hydrogen plasma, optical and electrical plasma diagnostics are performed. We report a periodic fluctuation in emission intensity and electric current in a dusty plasma. The trends of the frequency of fluctuations with varying substrate temperatures and gas flows are studied. However, no such fluctuation is observed in the nondusty plasma. It is hypothesized that this fluctuation arises from the periodic formation and ejection of a dust cloud via the void formation when a critical dust size is reached

Hot wire chemical vapour deposition process for producing an inorganic-polymer multi-layer stack

\u3cp\u3eThe invention provides a process for the production of a multi-layer stack comprising alternating layers of a polymeric material and an inorganic material, the process comprising a first formation process for the formation of a polymeric material layer or an inorganic material layer followed by a second formation process for the formation of the inorganic material layer or the polymeric material layer; wherein the first formation process and the second formation process comprise a hot wire chemical vapour deposition process using a wire at a predetermined wire temperature and a target substrate at a predetermined substrate temperature; wherein when the formation process comprises the formation of the polymeric material layer, the predetermined wire temperature is at maximum 230 DEG C; and wherein when the formation process comprises formation of the inorganic material layer, the predetermined substrate temperature is at maximum 110 DEG C. The invention also provides a device with such multi-layer stack.\u3c/p\u3

Optical transmission in a silicon nitride/polymer multilayer permeation barrier made by hot-wire CVD:Model and experiment

\u3cp\u3eThe optical transmission of silicon nitride/polymer multilayer permeation barriers was measured and compared with model calculations. With this model the individual layer thicknesses can be tailored to create specific transmission spectra.\u3c/p\u3

Chemical sputtering by H\u3csub\u3e2\u3c/sub\u3e \u3csup\u3e+\u3c/sup\u3e and H\u3csub\u3e3\u3c/sub\u3e \u3csup\u3e+\u3c/sup\u3e ions during silicon deposition

\u3cp\u3eWe investigated chemical sputtering of silicon films by H\u3csub\u3ey\u3c/sub\u3e \u3csup\u3e+\u3c/sup\u3e ions (with y being 2 and 3) in an asymmetric VHF Plasma Enhanced Chemical Vapor Deposition (PECVD) discharge in detail. In experiments with discharges created with pure H\u3csub\u3e2\u3c/sub\u3e inlet flows, we observed that more Si was etched from the powered than from the grounded electrode, and this resulted in a net deposition on the grounded electrode. With experimental input data from a power density series of discharges with pure H\u3csub\u3e2\u3c/sub\u3e inlet flows, we were able to model this process with a chemical sputtering mechanism. The obtained chemical sputtering yields were (0.3-0.4) ± 0.1 Si atom per bombarding H\u3csub\u3ey\u3c/sub\u3e \u3csup\u3e+\u3c/sup\u3e ion at the grounded electrode and at the powered electrode the yield ranged from (0.4 to 0.65) ± 0.1. Subsequently, we investigated the role of chemical sputtering during PECVD deposition with a series of silane fractions S\u3csub\u3eF\u3c/sub\u3e (S\u3csub\u3eF\u3c/sub\u3e(%) = [SiH\u3csub\u3e4\u3c/sub\u3e]/[H\u3csub\u3e2\u3c/sub\u3e]∗100) ranging from S\u3csub\u3eF\u3c/sub\u3e = 0% to 20%. We experimentally observed that the SiH\u3csub\u3ey\u3c/sub\u3e \u3csup\u3e+\u3c/sup\u3e flux is not proportional to S\u3csub\u3eF\u3c/sub\u3e but decreasing from S\u3csub\u3eF\u3c/sub\u3e = 3.4% to 20%. This counterintuitive SiH\u3csub\u3ey\u3c/sub\u3e \u3csup\u3e+\u3c/sup\u3e flux trend was partly explained by an increasing chemical sputtering rate with decreasing S\u3csub\u3eF\u3c/sub\u3e and partly by the reaction between H\u3csub\u3e3\u3c/sub\u3e \u3csup\u3e+\u3c/sup\u3e and SiH\u3csub\u3e4\u3c/sub\u3e that forms SiH\u3csub\u3e3\u3c/sub\u3e \u3csup\u3e+\u3c/sup\u3e.\u3c/p\u3