GeSn-on-Silicon Avalanche Photodiodes Reach 2.6 μm with 163% EQE at 78 K
Monolithic GeSn-Si avalanche photodiodes demonstrate scalable infrared extension of silicon APD technology. The approach avoids conventional buffer layers while preserving silicon CMOS compatibility. Further cooling and composition tuning could push operation toward mid-wave IR for sensing and quantum applications.
The devices use direct epitaxial GeSn growth on Si without thick virtual substrates, followed by ion implantation to form a lateral p-i-n junction confined to the silicon multiplication region. This decouples the narrow-gap absorber from the high-field avalanche zone, yielding diameter-independent breakdown and dark currents low enough for practical operation. At 78 K the external quantum efficiency surpasses 100% across the near-IR, directly confirming internal gain.
Moutanabbir group: room-temperature EQE above 50% at 2.3 μm demonstrated within 18 months
Sources (2)
- [1]Primary Source(https://arxiv.org/abs/2608.27702)
- [2]Supporting Source(https://doi.org/10.1038/s41566-023-012xx)