Mechanistic insights into photoplasticity of CdTe

K Luo and R Zhou and Q An, INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES, 305, 110765 (2025).

DOI: 10.1016/j.ijmecsci.2025.110765

Photoplasticity-the light-induced alteration of mechanical properties in semiconductors-is crucial for advancing optoelectronic devices and enhancing our understanding of semiconductor mechanics. Although significant progress has been made, the atomic-scale mechanisms underlying photoplastic effects (PPEs) remain only partially understood, particularly in CdTe, which exhibits both positive and negative PPEs. In this study, we develop machine learning potentials (MLPs) based on Density Functional Theory (DFT) and constrained DFT to investigate photoplasticity in CdTe. We focus on the Peierls stress and shear deformation behavior of critical dislocations-namely, the 30 degrees and 90 degrees partial dislocations-that control plasticity in both ground and excited states. Our simulations reveal that the photoplastic response in CdTe first increases and then decreases with rising excited electron-hole (e-h) concentrations, in agreement with experimental observations under varying light intensities. These results indicate a transition from positive to negative PPE, driven by a complex interplay of dislocation core reconstructions, phase transformations, and strongly coupled electronic-lattice interactions. This work reveals the critical role of light-dislocation interactions in PPEs and offers an efficient computational framework for studying photoplasticity in other semiconductors.

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