Fig. 4: Surface layer edge with positive potential to promote exciton dissociation along a axis. | Nature Communications

Fig. 4: Surface layer edge with positive potential to promote exciton dissociation along a axis.

From: Heavy-to-light electron transition enabling real-time spectra detection of charged particles by a biocompatible semiconductor

Fig. 4

a AFM image of surface layer-edges with a layer thickness of 1.5 nm (black scale bar: 150 nm), schematic diagram of layer edges promoted excitons dissociation along b a axis and c c axis (E is the electric field, LAED and EAED are Layer-Edge Assisted Exciton Dissociation and Electric-Field Assisted Exciton Dissociation processes, respectively), schematic diagram of surface layer-edge states in the energy band of 4HPA single crystals and its roles for d excitons dissociation along axis under dark condition, and anisotropic photocurrent along e a axis and f c axis (L1 and L2 are increased intensity of incident X-ray, RE, DT, and EDS are recombination, de-trap, and exciton dissociation processes, respectively), and g corresponding experimental results of anisotropic photocurrent of 4HPA single-crystal detectors along the a axis and the c axis (from left to right increase the power of incident X-ray beams) to prove the role of surface layer-edge states.

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