Catching Some Rays: A Look at the Present Status and Future Promise of Dye Sensitized Solar Cells

Jason B. Baxter

J. Vac. Sci. Technol. A 30, 020801 (2012);
doi:10.1116/1.3676433

Each day the sun bathes the earth with enough energy to power the entire global community many times over, but we currently capture only a tiny fraction of it. The relatively high cost of the electricity produced by traditional solar panels may be partly to blame for solar energy's bit part. "I think your best bet for expanding the use of solar energy is to make it at least as cheap as fossil fuels," says Professor Jason Baxter, a chemical engineering researcher at Drexel University in Philadelphia who studies solar cells. Baxter is the author of a review paper, recently published in the Journal of Vacuum Science and Technology A, that examines possible ways to improve the price/performance ratio of one promising form of solar energy technology: dye sensitized solar cells.

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The Surprising Importance of Photo-Assisted Etching of Silicon in Chlorine-Containing Plasmas

Hyungjoo Shin, Weiye Zhu, Vincent M. Donnelly, and Demetre J. Economou

J. Vac. Sci. Technol. A 30, 021306 (2012);
doi:10.1116/1.3681285

Using a plasma to etch patterns into silicon wafers is an essential step in many manufacturing processes. Now researchers from the University of Houston, in Texas, have demonstrated for the first time that the photons in chlorinecontaining plasma contribute to the etching process. While the effects of photoassisted etching are relatively small for high-energy plasmas, they become more noticeable at the low energies required for etching nanoscale patterns. The role of photons could help explain some defects, such as sloped sidewalls and microtrenches, that are sometimes found in plasma-etched silicon. Plasmas contain ions, electrons, and photons, and, in most etching applications, ions do the majority of the work to zap away silicon. High-energy ions, however, may wreck unintended damage on the patterned silicon. Lowering the energy of the ions can reduce the damage, and is required to etch fine, nanoscale patterns, but as the ion-etching rate slows, any effects from photo-assisted etching gain relative significance. Read more

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