Observation of bimolecular recombination in high mobility semiconductor Bi2O2Se using ultrafast spectroscopy

Bi2O2Se is emerging as a high mobility functional material for optoelectronics, but its fundamental optical properties remain less well studied. Here, ultrafast photocarrier dynamics in single crystal Bi2O2Se is investigated by pump fluence-dependent, broadband ultrafast spectroscopy. Our results reveal that bimolecular recombination plays an important role in the photocarrier relaxation process, and a room-temperature bimolecular recombination constant of (1.29 ± 0.42) × 10−9 cm−3 s−1 is obtained for Bi2O2Se. Such a level of the recombination constant combined with a high mobility (∼1006 cm2 V−1 s−1 at 200 K for Bi2O2Se) suggests that Bi2O2Se can be a promising material for photovoltaic applications.