GaAs epilayer films on Si substrates grown by molecular-beam epitaxy were investigated by the x-ray double-crystal diffraction method. The rocking curves were recorded for different diffraction vectors of samples. The results show that the unit-cell volumes of GaAs epilayers are smaller than that of the GaAs bulk material. The strained-layer superl...
The metallization of films by vacuum roll coating is a well known and established technique for production of high barrier packaging films. Despite the technical ability of producing such films there are general phenomena which are not understood at the moment: the mechanisms of gas permeation and adhesion, effects of both substrate properties as w...
The metallization of films by vacuum roll coating is a wellknown and established technique for production of high barrier packaging films. Despite the technical ability of producing such films there are general phenomena which are not understood at the moment: the mechanisms of gas permeation and adhesion, effects of both substrate properties as we...
Product take-back policies (such as the German "Verpackungsverordnung") are widely discussed today. The general principle behind such kinds of economy is the principle of material loops ("Kreislaufwirtschaft"). For achieving this target, to different strategies exist: Industrial material loops by means of material recycling in contrast to "biospher...
In Germany alone, the market for the packaging industry is approximately DM 40 Billion. A large portion of this is food packaging, where special demands are made for barrier requirements of packaging films. Through the use of thin substrate films and minimal coating material, vacuum coating processes can achieve barrier properties equivalent to tho...
Recently, we reported successful growth of high-quality GaAs/Si epilayers by using a very thin amorphous Si film as buffer layer. In this paper, the impurity properties of this kind of GaAs/Si epilayers have been studied by using PL spectrum, SIMS and Hall measurement. Compared to a typical PL spectrum of the GaAs/Si epilayers grown by conventional...
Because of the high cost and insufficient barrier properties against gases, water vapour and aromas, only limited use of biodegradable plastics for food packaging is possible. It is, however, possible to improve barrier propterties through vacuum coating of biodegradable films with of e.g. silicon monoxide or alumina. Yet, for the time being, insuf...
Single-crystal GaN films have been deposited on (01 (1) over bar 2) sapphire substrates using trimethylgallium (TMGa) and NH3 as sources. The morphological, crystalline, electrical and optical characterizations of GaN film are investigated. The carrier concentration ofundoped GaN increases with decreasing input NH3-to-TMGa molar flow ratio.
In the production of flexible packagings, the functionality plays a key role. Main required function is the barrier against gases, flavours and water vapour. The paper shows the barrier properties of selected packaging films in dependence on materials, processing, permeating substances and external influences.
Polymer films show some of the highest strength-to-weight ratios among packaging materials. Vacuum coating with thin barrier layers is now seen as a very promising method of improving their barrier properties.
