Tentative demonstration of all-silicon photodetector: from near-infrared to mid-infrared

Metastable silicon phases have attracted extensive attention these years, due to their fundamentally distinct photoelectric properties compared to the conventional diamond cubic (I) counterpart. Certain metastable phases, prepared via thermal heating method, can exhibit direct bandgap characteristics, significantly enhancing their light absorbance and quantum efficiency. Herein, we tentatively demonstrate an all-silicon photodetector working from near- to mid-infrared bands through precisely selective laser annealing strategy. We systematically investigated the optical properties and optoelectronic response of III/XII mixture, IV phase, and III/XII-I homojunctions. The obtained results reveal that III/XII composite and IV phase exhibit negative and positive photoconductivity, respectively. Furthermore, the established laser heating approach facilitates us to fabricate all-silicon homostructures with tunable photoconductive properties, such as III/XII-I and IV-I junctions. These findings can expand the potential applications of metastable semiconducting materials in optoelectronics and photodetectors.