Anisotropic Stress Response of Organic-Inorganic Hybrid Superlattice β-ZnTe(en)₀․₅ Revealed by Micro-Raman Spectroscopy

β-ZnTe(en)₀․₅ represents a unique 3-D hybrid superlattice with 2D like properties, in which two-monolayer-thick ZnTe (110) slabs are covalently linked by ethylenediamine molecules through Zn–N bonds. Its exceptional crystallinity and strongly anisotropic elastic response make it a prototype system for studying stress–phonon coupling in hybrid semiconductors.[1] We performed micro-Raman measurements under uniaxial loading to probe its vibrational response. Raman spectra reveal both red- and blue-shifting phonon modes under loading, reflecting mode-specific strain sensitivity. The coexistence of the modes with different stress responses highlights the competing effects of compressive and tensile strain components along different crystallographic directions, inherent to the anisotropic elastic response of this material. Under the applied stress, all spectra features maintain sharp and well-resolved, confirming long-range structural coherence and mechanical robustness. Preliminary results indicate the emergence of a new phonon mode at a stress around 0.25 GPa, suggesting a possible phase transition. Understanding such mode-selective phonon behavior under stress offers valuable insight into the mechanical stability, interfacial bonding, and strain-tunable functionality of hybrid superlattices, with potential implications for next-generation flexible optoelectronic and sensing devices.