GeSn shortwave infrared LED array prepared on GeSn nanostrips for on-chip broad-spectrum light sources

A GeSn nanostrip grown by the rapid melting growth method has gradient Sn content along the strip, a very attractive approach for making an infrared broad-spectrum light source. In this work, by applying the Sn content distribution strategy, GeSn shortwave infrared light-emitting diodes (LEDs) arrays with a size of 3 μm ×2 μm were fabricated on Si substrate, and the active layer Sn content increased from 2.1% to 5.2% to form a broadband light source. The GeSn LEDs show perfect rectifying behavior about 10 6 for ±1 V, and room temperature electroluminescence (EL) from the direct bandgap was achieved. The super-linear dependence between the injected current and EL intensity confirms the band-to-band radiative recombination. By utilizing Sn content gradient technology, the EL spectra of Sn gradient GeSn LED arrays can cover from 1600 to 2200 nm with a full width at half-maximum of about 340 nm. These results show a novel method for preparing broad-spectrum shortwave infrared light emitters on a Si chip.