Figure 1
From: Non-Radiative Carrier Recombination Enhanced by Two-Level Process: A First-Principles Study

Diagram to show the recombination process in a p-type material.
First, the defect level captures one electron from the CBM, releasing phonons; then, the defect level captures one hole from the VBM, releasing phonons and completing the recombination. This diagram is drawn by J.-H. Y.