High separation rate of epitaxial lift-off using hydrophilic solvent for III?V solar cell and reusable applications

Through the epitaxial lift-off (ELO) process using the HF solutions mixed with hydrophilic substances consisting of acetone (ACE), isopropanol (IPA), and methanol (MA), the separation rate for the GaAs substrate and the III-V solar cell can be improved significantly. Especially for the use of HF:ACE etchant, a extremely high lateral etching rate (14.3 μm/min) of the AlAs sacrificial layer can be achieved, as compared with that employing the pure HF etchant (3.6 μm/min). In addition, by conducting the ELO technique, the GaAs substrate was reused for four times, indicating its high potential for the reusable applications.