GeSn-on-insulator (GeSnOI) offers a highly compatible platform for silicon-based photonic integrated circuits (PICs). Using the modified Scheil theory, we design and realize a lateral type-I double heterojunction (DHJ) within a cross-shaped GeSnOI nanowire. Furthermore, high-temperature rapid annealing drives silicon diffusion into the surface GeSn layer, forming a vertical type-I DHJ based on a GeSiSn core–shell structure. With this tailored three-dimensional heterojunction architecture, we fabricate a Si-based light-emitting diode (LED) that achieves an external quantum efficiency exceeding 3%. This demonstration of a high-efficiency LED presents a key step toward future ultrascaled monolithic photonics, offering a viable pathway for high-density integration and advancing the development of fully silicon-based PICs.
Ye et al. (2026) studied this question.