Controllable Residual Stress Modulation of Diamond through High-Pressure and High-Temperature Annealing

Abstract

Diamond features superior optical, thermal, and mechanical properties, yet dislocation-induced uneven residual stress severely impairs optoelectronic device performance. Meanwhile, controllable uniaxial stress is required for applications like terahertz generators, making precise stress regulation vital for diamond application. Current stress modulation techniques mainly generate limited inhomogeneous compressive stress via mechanical loading, lacking feasible approaches to introduce homogeneous uniaxial stress. Previous studies found that high-pressure and high-temperature (HPHT) annealing reshapes diamond stress distribution, but the dislocation slip mechanism lacks systematic investigation. This study aims to regulate the stress of diamond through HPHT annealing. By combining indirect optical properties’ characterization, such as stress birefringence and Raman spectroscopy, systematically analyzed evolutions of optical homogeneity, residual stress, and point defects, with dislocation slip activation further interpreted by the Schmid critical resolved shear stress (CRSS) criterion. The results demonstrate that increasing annealing temperature optimizes stress distribution uniformity of (110) planes by activating dominant {111}⟨110⟩ slip systems for dislocation glide. Dislocation-driven plastic deformation homogenizes native, irregular residual stress on (110) surfaces and introduces extra uniform internal stress, while annealing at 2000 °C under 5 GPa for 120 min produces homogeneous residual stress over 1.2 GPa. This work offers a practical pathway for stress engineering of high-performance diamond optics.