Reduced Surface Recombination in Extended-Perimeter LEDs toward Electroluminescent Cooling.

III-V semiconductor light-emitting diodes (LEDs) are a promising candidate for demonstrating electroluminescent cooling. However, exceptionally high internal quantum efficiency designs are paramount to achieving this goal. A significant loss mechanism preventing unity internal quantum efficiency in GaAs-based devices is nonradiative surface recombination at the perimeter sidewall.

Metal diffusion barriers for GaAs solar cells.

In this study accelerated ageing testing (AAT), J-V characterization and TEM imaging in combination with phase diagram data from literature are used to assess the potential of Ti, Ni, Pd and Pt as diffusion barriers for Au/Cu-based metallization of III-V solar cells. Ni barriers show the largest potential as at an AAT temperature of 250 °C both cells with 10 and 100 nm thick Ni barriers show significantly better performance compared to Au/Cu cells, with the cells with 10 nm Ni barriers even showing virtually no degradation after 7.5 days at 250 °C (equivalent to 10 years at 100 °C at an E of 0.

A multi-nuclear magnetic resonance and density functional theory investigation of epitaxially grown InGaP2.

In this paper the short and long range order in In0.483Ga0.517P thin films is investigated by solid-state Nuclear Magnetic Resonance (NMR) spectroscopy.

Degradation mechanism(s) of GaAs solar cells with Cu contacts.

Substrate-based GaAs solar cells having a dense Au/Cu front contact grid with 45% surface coverage were exposed to accelerated life testing at temperatures between 200 and 300 °C. TEM analysis of the front contacts was used to gain a better understanding of the degradation process. During accelerated life testing at 200 °C only intermixing of the Au and Cu in the front contact occurs, without any significant influence on the J-V curve of the cells, even after 1320 h (55 days) of accelerated life testing.

Maximal power output by solar cells with angular confinement.

Angularly selective filters can increase the efficiency of radiatively limited solar cells. A restriction of the acceptance angle is linked to the kind of utilizable solar spectrum (global or direct radiation). This has to be considered when calculating the potential enhancement of both the efficiency and the power output.