Towards an Optimized All Lattice-Matched InAlAs/InGaAsP/InGaAs Multijunction Solar Cell with Efficiency >50%

An approach for an all lattice-matched multijunction solar cell optimized design is presented with 5.807 Å lattice constant, together with a detailed analysis of its performance by means of full device modeling. The simulations show that a (1.93 eV)In_0.37Al_0.63As/(1.39 eV)In_0.38Ga_0.62As_0.57P_0.43/(0.94 eV)In_0.38Ga_0.62As 3-junction solar cell can achieve efficiencies >51% under 100-suns illumination (with V_oc = 3.34 V). As a key proof of concept, an equivalent 3-junction solar cell lattice-matched to InP was fabricated and tested. The independently connected single junction solar cells were also tested in a spectrum splitting configuration, showing similar performance to a monolithic tandem device, with V_oc = 1.8 V.