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Iron Pyrite (FeS2) Broad Spectral and Magnetically Responsive Photodetectors



Earth-abundant iron pyrite (FeS2) nanocrystals show great potential in broad photosensing applications due to their high photoabsorption coefficient (>105 cm−1) and ideal bandgap (0.95 eV). However, broad spectral photodetectors using the FeS2 nanojunctions and external stimuli-driven photoresponse have not been demonstrated yet. Here, broad spectral FeS2/CdS bulk nanojunction photodetectors are demonstrated, covering the UV-Vis-NIR wavelength range. This is the first time shape-dependent FeS2 nanocrystals and a dilute magnetic semiconductor phase exhibiting fast photoresponse time (10 ms) and high responsitivity (174.9 A/W) is demonstrated. Tunable photocurrent (73% change) is observed under the magnetic field effect due to the interdiffusion-controlled diluted magnetic semiconductor CdFeS phase. The broad spectral FeS2-based photodetectors open up a new tactic for solution-processed next generation efficient and sustainable photosensing devices.