Boosting SHG in InP Nanomembranes: The Role of the Wurtzite-Zincblende Polytypic Interface

III–V semiconductors, particularly InP, have demonstrated significant potential for seamless integration into nanophotonic systems. However, conventional zincblende InP crystals exhibit inherently weak second-harmonic generation (SHG) due to limited second-order nonlinear susceptibility, presenting a major challenge for developing effective nonlinear optical components in integrated photonic circuits. Here, it is demonstrated that large-area biphasic wurtzite-zincblende (WZ–ZB) interfaces can remarkably enhance SHG in InP nanomembranes, yielding up to a 200-fold intensity increase in the short-wave infrared range. This enhancement stems from the type-II band alignment at the polytypic interface, which spatially separates photogenerated carriers, prolonging carrier lifetimes and sustaining a strong nonlinear polarization source. The abrupt phase boundary and the nanomembrane's large surface-to-volume ratio introduce additional symmetry-breaking at the interface, which further amplifies the SHG signal. The polarization dependence of SHG and the resulting SHG-induced photoluminescence exhibit anisotropic features. The results establish crystalline phase engineering in WZ–ZB InP homostructures as a highly effective strategy for tailoring nonlinear optical processes, offering new pathways for high-efficiency wavelength conversion and integrated on-chip nonlinear photonic circuits.

Duke Scholars

Author Changcheng Zheng DKU Faculty