High conversion efficiency and radiation resistant InP solar cell

This paper presents an investigation of the p⁺-i-n junction structure InP solar cells fabricated on n-type InP substrates by a liquid phase epitaxial (LPE) growth method using Mg as a p-type dopant. It was found that the junction depth and structure could be controlled by use of Mg diffusion properties during LPE growth. The conversion efficiencies of p⁺-i-n structure cells are as high as 21.5% at AM 1.5 and 17.2% at AM 0, which are the highest ever reported. The radiation resistance of the p⁺-i-n structure cell was not as good as the n⁺-p structure cell because of an increase in the leakage current due to the recombination center introduced in the i-layer with irradiation. Its radiation resistance has been found to be improved by optimizing i-layer thickness for the p⁺-i-n structure cell.