InP based engineered substrates for CPV cells above 46% of efficiency

By facilitating material recycling, Smart Cut ⢠technology enables the cost-effective use of expensive bulk material such as InP. In addition to this cost advantage, different handle substrates such as GaAs, Sapphire or Ge have been evaluated to enable new functions: receiver lift off, lower fragility, better integration. We have demonstrated the recycling of the InP wafer up to 7 times and evaluated up to 10 cycles. Using the InP-on-GaAs engineered substrate combined with direct wafer bonding, Soitec together with Fraunhofer ISE and CEA Leti have demonstrated wafer bonded 4-junction solar cells with highest conversion efficiency of 46.1 %. In parallel, equivalent solar cell performances are demonstrated either on bulk InP substrate or InP engineered substrate.