The fourth international conference on dense z-pinches, 1997
ABSTRACT Results of experiments studying the effect of a ringing 10 kA current prepulse on a 160 ... more ABSTRACT Results of experiments studying the effect of a ringing 10 kA current prepulse on a 160 kA, 7 mum carbon fibre z-pinch are presented. A prepulse duration of 100-300 ns was found to radically alter the pinch behaviour. A delayed onset in x-ray and optical emission with respect to the main current was observed. There was a marked improvement of axial uniformity in the pinch. A large soft x-ray pulse, ten to twenty times larger than in discharges without prepulse was recorded. An electron temperature of 250+/-50 eV was measured which was considerably higher than in the discharges without prepulse.
Plasma formation and x-ray generation efficiency of a carbon fiber Z pinch are dramatically impro... more Plasma formation and x-ray generation efficiency of a carbon fiber Z pinch are dramatically improved by means of an optimized current prepulse. In this article results are presented of time-integrated and also time-resolved electron temperature measurements using the optical line emission of the coronal plasma surrounding a still, cold fiber. Two phases of discharges with current prepulse are studied: the preionization phase only in which time-integrated spectra of C II–C IV emission are recorded and time resolution of the heating phase after onset of the main current pulse using C III and C IV line emission. Experimentally obtained, n=3–4, 3–3, line ratios are fitted with collisional radiative, ADAS computations of line intensity ratios as a function of electron temperature, density, ne and variable confinement, τ. All levels up to n=5 are included with the influence of higher levels also accounted for. Deviations from coronal balance give an effective value for the product 〈neτ〉. ...
Metal-Semiconductor-Metal photodiodes were fabricated on epitaxially grown AlxGa1-xN on Si(111). ... more Metal-Semiconductor-Metal photodiodes were fabricated on epitaxially grown AlxGa1-xN on Si(111). The Aluminium content of the layers grown by means of molecular beam epitaxy (MBE) was 50, 80 and 100%, respectively. The processing was performed by standard microelectronic fabrication techniques like photolithography, wet and dry etching (RIE) and physical and chemical vapor deposition (PVD,CVD). The devices were characterized under illumination in
This work proves that blistering is the partial delamination of a thick enough Al2O3 layer caused... more This work proves that blistering is the partial delamination of a thick enough Al2O3 layer caused by gaseous desorption in the Al2O3 layer upon thermal treatments above a critical temperature: the Al2O3 layer acts as a gas barrier and bubble formation occurs. First, using an atmospheric pressure rapid thermal processor with an atmospheric pressure ionization mass spectrometry, desorbing species upon
Rear side passivated c-Si solar cells are gaining in the last years particular interest by resear... more Rear side passivated c-Si solar cells are gaining in the last years particular interest by research organisation and industrial solar cell manufacturers. Those devices typically rely on chemically polished rear surfaces before applying dielectric passivation layers. It is the purpose of this work to study the influence of the rear side polishing step on the performance of CZ-Si solar cells that have been textured with in-line alkaline texturing equipment for the formation of random pyramids on the front side of the wafer. Varying the chemical polishing step for the rear surface preparation, the surface roughness and its optical properties have been investigated with respect to the overall solar cell performance of screen printed solar cells with homogeneous emitter and rear side passivated surfaces with local Al BSF contacts. A wide process window was found for the rear side polishing process not requiring for perfectly polished rear surfaces when aiming for efficiencies above 19%. ...
If the world's answer to alternative energy production is to be silicon photo... more If the world's answer to alternative energy production is to be silicon photovoltaics, the fabricated devices need to be robust and highly efficient in varying operating conditions. Rear oxide passivated local Al-BSF cells have a prevalent issue that hinders their performance in particular operating conditions, this issue being bias light dependence (reduced response at low illumination levels). It has been
The fourth international conference on dense z-pinches, 1997
ABSTRACT Results of experiments studying the effect of a ringing 10 kA current prepulse on a 160 ... more ABSTRACT Results of experiments studying the effect of a ringing 10 kA current prepulse on a 160 kA, 7 mum carbon fibre z-pinch are presented. A prepulse duration of 100-300 ns was found to radically alter the pinch behaviour. A delayed onset in x-ray and optical emission with respect to the main current was observed. There was a marked improvement of axial uniformity in the pinch. A large soft x-ray pulse, ten to twenty times larger than in discharges without prepulse was recorded. An electron temperature of 250+/-50 eV was measured which was considerably higher than in the discharges without prepulse.
Plasma formation and x-ray generation efficiency of a carbon fiber Z pinch are dramatically impro... more Plasma formation and x-ray generation efficiency of a carbon fiber Z pinch are dramatically improved by means of an optimized current prepulse. In this article results are presented of time-integrated and also time-resolved electron temperature measurements using the optical line emission of the coronal plasma surrounding a still, cold fiber. Two phases of discharges with current prepulse are studied: the preionization phase only in which time-integrated spectra of C II–C IV emission are recorded and time resolution of the heating phase after onset of the main current pulse using C III and C IV line emission. Experimentally obtained, n=3–4, 3–3, line ratios are fitted with collisional radiative, ADAS computations of line intensity ratios as a function of electron temperature, density, ne and variable confinement, τ. All levels up to n=5 are included with the influence of higher levels also accounted for. Deviations from coronal balance give an effective value for the product 〈neτ〉. ...
Metal-Semiconductor-Metal photodiodes were fabricated on epitaxially grown AlxGa1-xN on Si(111). ... more Metal-Semiconductor-Metal photodiodes were fabricated on epitaxially grown AlxGa1-xN on Si(111). The Aluminium content of the layers grown by means of molecular beam epitaxy (MBE) was 50, 80 and 100%, respectively. The processing was performed by standard microelectronic fabrication techniques like photolithography, wet and dry etching (RIE) and physical and chemical vapor deposition (PVD,CVD). The devices were characterized under illumination in
This work proves that blistering is the partial delamination of a thick enough Al2O3 layer caused... more This work proves that blistering is the partial delamination of a thick enough Al2O3 layer caused by gaseous desorption in the Al2O3 layer upon thermal treatments above a critical temperature: the Al2O3 layer acts as a gas barrier and bubble formation occurs. First, using an atmospheric pressure rapid thermal processor with an atmospheric pressure ionization mass spectrometry, desorbing species upon
Rear side passivated c-Si solar cells are gaining in the last years particular interest by resear... more Rear side passivated c-Si solar cells are gaining in the last years particular interest by research organisation and industrial solar cell manufacturers. Those devices typically rely on chemically polished rear surfaces before applying dielectric passivation layers. It is the purpose of this work to study the influence of the rear side polishing step on the performance of CZ-Si solar cells that have been textured with in-line alkaline texturing equipment for the formation of random pyramids on the front side of the wafer. Varying the chemical polishing step for the rear surface preparation, the surface roughness and its optical properties have been investigated with respect to the overall solar cell performance of screen printed solar cells with homogeneous emitter and rear side passivated surfaces with local Al BSF contacts. A wide process window was found for the rear side polishing process not requiring for perfectly polished rear surfaces when aiming for efficiencies above 19%. ...
If the world's answer to alternative energy production is to be silicon photo... more If the world's answer to alternative energy production is to be silicon photovoltaics, the fabricated devices need to be robust and highly efficient in varying operating conditions. Rear oxide passivated local Al-BSF cells have a prevalent issue that hinders their performance in particular operating conditions, this issue being bias light dependence (reduced response at low illumination levels). It has been
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