Publications

AlGaAs/InGaAlP tunnel junctions for multi-junction solar cells

Sharps, P.R.; Li, N.Y.; Hills, J.S.; Hou, H.Q.; Chang, P.C.; Baca, A.

A number of different high bandgap tunnel junctions have been examined for use in advanced monolithic multi-junction solar cells. All of the tunnel junctions are grown by metal-organic vapor phase epitaxy. An Al0.9Ga0.1As/In0.5Ga0.3Al0.2P tunnel junction has the necessary optical and electrical properties for use in an advanced four junction device, and we demonstrate a working device. The bandgap of the Al0.9Ga0.1As and the In0.5Ga0.3Al0.2P are both 2.1 eV. The Jp of the device is 1,500 mA/cm2, and the series resistance is 2.5 × 10-2 Clcm2. The Al0.9Ga0.1As is doped with carbon, while the In0.5Ga0.3Al0.2P is doped with tellurium. SIMS analysis indicates minimal tellurium memory effect and outdiffusion, and hence minimal tellurium doping in ensuing layers.