Direct Spatiotemporal Imaging of Charge Carrier Dynamics in Operative Semiconductor Devices
Understanding charge carrier dynamics within electronic devices is crucial, as it governs both the internal evolution of signals and the externally measurable current. Yet, direct imaging of these dynamics remains elusive: existing approaches are often indirect or inherently perturbative. Here, we introduce Carrier Dynamics by Pockels Imaging (CDPI), a sensitive, quantitative, and non-invasive method that enables direct access to internal charge dynamics. By probing the local electric field, CDPI visualizes photogenerated electron clouds in real space while simultaneously correlating their evolution with both conduction and displacement currents, thereby establishing a unified picture of carrier transport. The technique provides direct insight into fundamental mechanisms \textemdash including drift, diffusion, carrier-carrier interactions, trapping and detrapping \textemdash as well as the spatiotemporal evolution of carrier cloud morphology. Demonstrated in CdTe radiation detectors with micrometre-scale spatial resolution and nanosecond temporal resolution, CDPI is broadly applicable to systems exhibiting appreciable electro-optic responses. Beyond conventional semiconductors, the approach extends to organic, perovskite, and two-dimensional optoelectronic materials, offering a new paradigm for directly linking internal carrier dynamics to device-level functionality.