[J. Phys. Chem. Lett.] 我室张洪良教授和杨晔教授发表论文:Micro-Heterogeneous Annihilation Dynamics of Self-Trapped Excitons in Hematite Single Crystals

发布日期:2020年09月07日   浏览次数:

我室张洪良教授和杨晔教授在 J. Phys. Chem. Lett. 上发表论文:Micro-Heterogeneous Annihilation Dynamics of Self-Trapped Excitons in Hematite Single Crystals


摘要:The Auger recombination in bulk semiconductors can quickly depopulate the charge carriers in a nonradiative way, which, fortunately, only has a detrimental impact on optoelectronic device performance under the condition of high carrier density because the restriction arising from concurrent momentum and energy conservation limits the Auger rate. Here, we surprisingly observed enhanced Auger recombination in an α-Fe2O3 single crystal, a wide bandgap semiconductor with low carrier mobility. The Auger process was ascribed to the Coulombically coupled self-trapped excitons (STEs), and the relaxation of momentum conservation due to the strong spatial localization of these STEs should account for the enhancement. The STE-density dependent kinetics suggested that the strong polaronic effect could cause a micro-heterogeneous distribution of STEs in a high-quality bulk single crystal, which also gave rise to the micro-heterogeneous annihilation dynamics, and a stochastic recombination model was developed and successfully described the STE annihilation dynamics.