Passivation of Indium-Phosphide Solar Cells

The high front surface recombination velocity (SRV) exhibited by indium phosphide (InP) solar cells has limited the level of efficiency that has been demonstrated to date. Gallia has developed metal organic chemical vapor deposition (MOCVD) methodology to enable the growth of a previously unknown wide band gap (4 eV) cubic-phase of gallium sulfide (GaS), which has been demonstrated to passivate III-V surfaces. Gallia's sulfide based coating will provide a proccessable method for the passivation of InP solar cell surfaces. The project objectives include: growth of high purity GaS films on InP, determination of the extent of surface passivation, fabrication and testing of GaS passivated InP solar cells, determination of GaS long term stability, and development of alternative III-VI passivation materials. Gallia will commit 900 man hours to these objectives. It is anticipated that the as a result of this program Gallia will be able to fabricate, by MOCVD, a series of gallium chalcogenide-based passivation coatings for InP solar cells. It is expected that the results of this project will benefit NASA in the possible fabrication of high efficiency InP solar cells for non-terrestrial applications.