Accurate measurement of extremely low surface recombination velocities on charged, oxidized silicon surfaces using a simple metal-oxide-semiconductor structure

The authors report a simple technique to determine the surface recombination velocity of silicon and other semiconductor surfaces which have been passivated with a dielectric layer, as a function of charge density. A metal-oxide-semiconductor structure, employing large area, partially transparent metal contacts, is used to enable the charging of the surfaces. Simultaneous measurement of the emitter saturation current density Jœ and the effective instantaneous lifetime τinst allows accurate extraction of the effective surface recombination velocity Seff at any given injection level. Extremely low Jœ values of 1.8 fA cm-2 are measured on the silicon-silicon oxide (Si–SiO2) interface of a thermally oxidized, charged wafer

Defect generation at the Si–SiO₂ interface following corona charging

A combination of capacitance-voltage and lifetime decay measurements is used to show that corona biasing of silicon oxidized samples results in the generation of additional interface defects and an increase in surface recombination. The onset of interface degradation occurs at relatively low electric fields, estimated to be less than ∼+∕−1.2MV∕cm. The majority of the defects generated by corona biasing can be removed by a short annealing at 400°C. The results are consistent with the hypothesis that atomic hydrogen is chiefly responsible for the observed degradation. Corona biasing, even at low electric fields, cannot be relied on as a noninvasive characterization tool.Support from the Australian Research Council for this work is acknowledged

Recent developments in SLIVER cell technology

SLIVER cells, which were invented and developed at the ANU, allow the production of thin silicon cells and modules from standard silicon wafers, without the requirement for silicon deposition or any other expensive steps. Reductions in silicon consumption by a factor of 7-12 and reductions in the number of wafers that need to be processed per MW of a factor of 12-40 are possible. SLIVER cells are fabricated with sophisticated processing on high quality single crystal silicon substrates. SLIVER cell efficiencies above 19% are the highest reported for any commercially-viable thin-film cell. In this paper we report that a new SLIVER process has been devised that has the potential to double the throughput of a factory compared with the older SLIVER process

3D Printing Temperature Tailors Electrical and Electrochemical Properties through Changing Inner Distribution of Graphite/Polymer

The rise of 3D printing technology, with fused deposition modeling as one of the simplest and most widely used techniques, has empowered an increasing interest for composite filaments, providing additional functionality to 3D-printed components. For future applications, like electrochemical energy storage, energy conversion, and sensing, the tuning of the electrochemical properties of the filament and its characterization is of eminent importance to improve the performance of 3D-printed devices. In this work, customized conductive graphite/poly(lactic acid) filament with a percentage of graphite filler close to the conductivity percolation limit is fabricated and 3D-printed into electrochemical devices. Detailed scanning electrochemical microscopy investigations demonstrate that 3D-printing temperature has a dramatic effect on the conductivity and electrochemical performance due to a changed conducive filler/polymer distribution. This may allow, e.g., 3D printing of active/inactive parts of the same structure from the same filament when changing the 3D printing nozzle temperature. These tailored properties can have profound influence on the application of these 3D-printed composites, which can lead to a dramatically different functionality of the final electrical, electrochemical, and energy storage device