AbstractNonlinear emission characteristics of (111)‐oriented diamond p–i–n junction light‐emitting diodes (LEDs) were investigated. We measured the superlinear increase of excitonic emission and sublinear increase of deep‐level emission due to defects and/or impurity centers depending on injected current at room temperature (RT). These characteristics could not be explained by conventional carrier trapping and recombination processes at deep levels based on simple Shockley–Read–Hall statistics. We introduced three‐step processes of carrier trapping and recombination at charged deep levels via bound states, where the bound states are stable even at RT because of low dielectric constant in diamond. Rate equation analysis based on this concept simultaneously explained the superlinear increase of excitonic emission and sublinear increase of deep‐level emission for diamond LEDs.