Mid‐Infrared LEDs Based on Lattice‐Mismatched Hybrid IV–VI/III–V Heterojunctions

ABSTRACT Light‐emitting diodes (LEDs) can bridge the gap between narrow linewidth, expensive lasers and broadband, inefficient thermal globars for low‐cost chemical sensing in the mid‐infrared (mid‐IR). However, the efficiency of III–V‐based mid‐IR LEDs at room temperature is low, primarily limited by strong nonradiative Auger‐Meitner recombination that is only partially overcome with complex quantum‐engineered active regions. Here, we exploit the intrinsically low Auger‐Meitner recombination rates of the IV–VI semiconductors PbSe and PbSnSe, while leveraging the mature III–V platform through the fabrication of hybrid heterojunctions that mediate the ∼8% lattice mismatch to GaAs. Electrically injected n‐PbSe/p‐GaAs LEDs emit at 3.8 µm with output powers up to 400 µW under pulsed operation and a peak wall plug efficiency of 0.08% at room temperature, approaching the performance of commercial III–V LEDs at similar wavelengths. Incorporating 7% Sn extends the emission to 5 µm in GeSe/PbSnSe/GaAs LEDs with output powers up to 45 µW. Notably, both devices operate despite threading dislocation densities on the order of 10 9 cm −2 , underscoring the potential of hybrid IV–VI/III–V heterojunction architectures. We show that combining the complementary advantages of IV–VI and III–V semiconductors offers a simple and efficient mid‐IR optoelectronic platform for a rapidly expanding set of applications.