InA1As/InGaAs low-band-gap cell on InP for high efficiency multi-structure solar cell system

InA1As/InGaAs solar cells on InP for a low-band-gap cell have been fabricated. From theoretical simulation it is expected that the optimized InA1As/InGaAs cell should have photovoltaic characteristics values of J_sc = 21.2 mA cm⁻², V_oc = 0.345 V, FF = 0.745 and ν = 4.02% at one sun AM0 without an AR-coating. The best performance achieved by experiment was J_sc = 22.0 mA cm⁻², V_oc = 0.320 V, FF = 0.695, ν = 3.61% without an AR-coating. The uniformity of the characteristics was much improved utilizing the InGaAs cap layer for a low contact resistivity.