Optoelectronic properties and ultrafast carrier dynamics of copper iodide thin films

As a promising high mobility p-type wide bandgap semiconductor, copper iodide has received increasing attention in recent years. However, the defect physics/evolution are still controversial, and particularly the ultrafast carrier and exciton dynamics in copper iodide has rarely been investigated. Here, we study these fundamental properties for copper iodide thin films by a synergistic approach employing a combination of analytical techniques. Steady-state photoluminescence spectra reveal that the emission at -420 nm arises from the recombination of electrons with neutral copper vacancies. The photogenerated carrier density dependent ultrafast physical processes are elucidated with using the femtosecond transient absorption spectroscopy. Both the effects of hot-phonon bottleneck and the Auger heating significantly slow down the cooling rate of hot-carriers in the case of high excitation density. The effect of defects on the carrier recombination and the two-photon induced ultrafast carrier dynamics are also investigated. These findings are crucial to the optoelectronic applications of copper iodide.

Automated summary

Copper iodide, as a promising high mobility p-type wide bandgap semiconductor, has attracted increasing attention. However, the defect physics/evolution and ultrafast carrier and exciton dynamics in copper iodide are still controversial and rarely investigated. In this study, the fundamental properties of copper iodide thin films are investigated using a combination of analytical techniques. The results provide insights into the photogenerated carrier density dependent ultrafast physical processes and the effects of defects on carrier recombination and two-photon induced ultrafast carrier dynamics. These findings are crucial for the optoelectronic applications of copper iodide.