A new approach for Multi junction solar cells from off the shelf individual cells: GaAs/Si

We present a low temperature and low pressure approach to multijunction solar cell fabrication combining the high efficiency multi-junction concept with the low cost of thin film technology in one solar cell structure. The intermetallic bonding approach presented bonds indium metal covering metal contacts of the respective solar cells. This approach avoids lattice mismatch and tunnel junction limitations in connecting solar cells of any material and permits bonding of commercial off the shelf devices or textured surfaces. A two or three terminal GaAs/Si multijunction solar cell bonded using this approach is demonstrated using an off the shelf Si solar cell.