Pseudo Direct Semiconductor

Study finds Bi2S3 semiconductor exhibits unusually slow electron-hole recombination

Researchers used terahertz, millimetre-wave conductivity, and photoluminescence probes to track photoexcited charge carriers in bismuth sulfide (Bi2S3) thin films over timescales from 200 femtoseconds to 1 microsecond. They found that most carriers recombine within about 100 nanoseconds via defect-mediated trapping, while at higher excitation intensities and shorter picosecond timescales, an intrinsic electron-hole recombination process dominates. The team modeled these combined behaviors using a rate equation that separates defect-related and intrinsic recombination contributions.