An effective way to improve polymer solar cell efficiency is to use a tandem structure, as a broader part of the spectrum of solar radiation is used and the thermalization loss of photon energy is minimized. In the past, the lack of high-performance low-bandgap polymers was the major limiting factor for achieving high-performance tandem solar cell. Here we report the development of a high-perfo...

S.Y. Zhou, 2 D.A. Siegel, 2 A.V. Fedorov, F. El Gabaly, A. K. Schmid, A.H. Castro Neto, and A. Lanzara 2 Department of Physics, University of California, Berkeley, CA 94720, USA Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA Department of Physics, Boston Uni...

Emission dynamics of two InGaN/GaN single quantum well red emitters were investigated through timeresolved photoluminescence (PL) spectroscopy. A clear phase separation, where a higher energy (blue) emission and a lower energy (red) emission appear simultaneously, was observed. The maximum position of blue emission is consistent with the bandgap value of the InGaN quantum well. As the time afte...

We report on the generation of THz waves through optical rectification in ZnTe femtosecond laser pulses whose photon energy is tuned from below to above bandgap energy. The signal exhibits a pronounced peak at energy, frequencies for which losses remain small. This likely due resonance nonlinear susceptibility vicinity bandgap.

A probing technique to obtain the energy distribution of positive charges in high-k gate stack dielectrics, both within and beyond the substrate bandgap, has been proposed. The energy distribution of different high-k devices has been investigated and attention has been paid to their differences from the single-layered SiON devices. The results obtained from the technique demonstrate the existen...

This article evokes the futuristic visions of two giants, one a writer, Jules Verne, who foresaw water as the coal of the future, and the other a scientist, Giacomo Ciamician, who foresaw the utilization of solar energy as an energy source with which to drive photochemical and photocatalytic reactions for the betterment of mankind. Specifically, we examine briefly the early work of the 1960s an...

We report room-temperature electroluninescence at Si bandgap energy from Metal-Oxide-Semiconductor (MOS) tunneling diodes. The Ultrathin gate oxide with thickness 1 3 urn was grown by rapid thennal oxidation (RTO) to allow significant current to tunnel through. The measured EL efficiency of the MOS tunneling diodes increases with the injection current and could be in the order of iO, which exce...