Photomechanical Effect Leading To Extraordinary Ductility In Covalent Semiconductors

Covalent semiconductors play an important role in key technological advancements in areas such as communications, consumer electronics, automotive, energy, and more. However, the low ductility of covalent semiconductors, originating from the strong chemical bonding, prevents them from a wide range of engineering applications. In this work, we demonstrate that the bond strength of covalent materials is very sensitive to the electron distribution, able to be effectively modified via the electron-hole pairs (EHPs) induced by photoexcitation. The photomechanical effects in the III-V covalent semiconductors GaP, GaAs, and InP have been examined by a combination of advanced quantum mechanics (QM) simulations, nanoindentation experiments, and state-of-the-art transmission electron microscopy measurements. The QM results indicate that the energy barrier for deformation slip in GaP is reduced by more than 50% by generating high-concentration EHPs (similar to 10(21) cm(-3)), exhibiting metal-like ductility. Theoretical prediction agrees very well with the experimental measured performance where more dislocations are activated under light-illumination conditions.