Exciton-biexciton dynamics in an organic-inorganic hybrid quantum-well material

Summary form only given. Excitonic optical properties have been extensively studied in a large variety of semiconductors, and it has been found that biexciton formation and relaxation play an important role in the nonlinear optical processes. The binding energies of biexcitons in typical semiconductors, however, are less than 10 meV so that it is difficult in femtosecond spectroscopy to distinguish the biexciton process from a single exciton process. In order to study the exciton-biexciton system in detail, a large binding energy of the biexciton is required. In this paper we report on the biexcitons with extremely large binding energy (= 66 meV) in an organic-inorganic hybrid quantum-well material, (C/sub 4/H/sub 9/NH/sub 3/)/sub 2/PbBr/sub 4/. This material belongs to the layered perovskite-type quantum-well materials (C/sub n/H/sub 2n+1/NH/sub 3/)/sub 2/PbX/sub 4/ which have excitons with large binding energy. We investigate the dynamics of such a stable exciton-biexciton system.