Comparison of various InGaAs-based solar cells for concentrated photovoltaics applications

International audience; InGaAs lattice matched to InP is a promising material for bottom sub-cell in a 4-junction solar cell designed for concentrated photovoltaics applications. Here we compare the performances of two structures that could replace standard monolithic InGaAs homojuntion. The first one is a stand-alone solar cell realized via epitaxial lift-off (ELO) process on a flexible substrate. The second one is a heterojunction solar cell, kept on its parent InP substrate, composed of an InP emitter and an InGaAs absorber. A third structure made of an homojunction InGaAs solar cell on an InP substrate is used as reference. Under one sun illumination the heterojunction solar cell shows the highest VOC (383 mV) and fill factor. Nevertheless, when performing under concentrated sunlight the structure is limited by a lower VOC increase rate and a high series resistance compared to the ELO cell. Indeed, ELO cell shows a lower VOC (353 mV) than the two other structures under one sun illumination but, when performing under concentration, ELO cell recovers VOC and shows a lower impact of series resistance. Therefore, both ELO and heterojunction solar cell show interesting and complementary behaviors that could be interesting to associate in an ELO-heterojunction solar cell.