17.2-percent efficient (AMO) p+-i-n InP homojunction solar cells

p⁺-i-n junction structure InP solar cells have been fabricated on n-type substrates by the LPE method. The conversion efficiencies for the active area of this cell are as high as 21.5 percent at AM1.5 and 17.5 percent at AMO, respectively. These are the highest ever reported for InP. The radiation resistance to 1-MeV electrons can be improved by optimizing i-layer thickness to 1 µm. However, the radiation-resistance of the p⁺-i-n cell is not so good as the n⁺-p structure cell, because of the increase in the leakage current due to the recombination center introduced in the i-layer with irradiation.