Fast deposition of amorphous carbon and silicon layers

A new plasma deposition technique is described. In this method a high density and strongly flowing argon plasma is admixed with monomers such as CH/sub 4/, C/sub 2/H/sub 2/, SiH/sub 4/, etc. Through effective charge transfer and dissociative recombination the ion charge is transferred to the fully dissociated monomer fragments. As the to be deposited particles as C and Si have low ionization potentials they are preferably recharged. The method results in high deposition rates of a-C:H (up to 100 nm/s) and a-Si:H layers (30 nm/s). Properties of the layers are reviewed and a tentative model for plasma description is discusse

Duurzame landbouw in een schakelkast

Diverse benaderingen helpen bij het denken over transitie naar duurzame landbouw. In deze rapportage worden de sectorale benadering, de ketenbenadering en de ruimtelijke benadering naast elkaar gezet, waarbij wordt aangegeven wat sterke punten zijn en waar ze tegen grenzen aan lopen. Vervolgens is gekeken een integrale benadering het meest passend is om te komen tot paden richting duurzame landbouw. Dit blijkt niet het geval. Het lijkt erop dat het meeste rendement kan worden behaald als in de eerste fase van een transitieproces alle drie de benaderingen tegelijk worden betrokken in het proces, terwijl er in latere fases kan worden geschakeld tussen de benaderinge

Analysis of the evolution of a supersonically expanding plasma

A supersonically expanding arc plasma in argon is analyzed both experimentally and theoretically. The plasma is created in a cascaded arc and extracted through a hole in the anode. It emanates in a large vacuum system, where it expands supersonically. This expansion is limited by a shock wave. After the shock wave a subsonic plasma beam is created. A quasi one-dimensional model, based on the conservation of mass, momentum and energy is presented. The shock wave is treated as a discontinuity. The electron density, the gas velocity and the gas temperature are measured as a function of the position in the expansion by means of Stark broadening and Doppler spectroscopy. The model calculations agree well with the measurements, especially in the first part of the supersonic flo

Analysis of the evolution of a supersonically expanding plasma

A supersonically expanding arc plasma in argon is analyzed both experimentally and theoretically. The plasma is created in a cascaded arc and extracted through a hole in the anode. It emanates in a large vacuum system, where it expands supersonically. This expansion is limited by a shock wave. After the shock wave a subsonic plasma beam is created. A quasi one-dimensional model, based on the conservation of mass, momentum and energy is presented. The shock wave is treated as a discontinuity. The electron density, the gas velocity and the gas temperature are measured as a function of the position in the expansion by means of Stark broadening and Doppler spectroscopy. The model calculations agree well with the measurements, especially in the first part of the supersonic flo