Identify the physical basis of the nonlinear depletion trap

Identify a specific physical mechanism that motivates the nonlinear depletion trap introduced into the modified multiple-trap rate-equation model to reproduce the large step-up overshoot observed in amorphous-silicon flat-panel detectors.

Background

The modified rate-equation model introduces a fifth trap and a nonlinear radiationless recombination term involving conduction electrons, holes, and the population of the fifth trap. This term was added to account for the nonlinear overshoot observed during large step-up transitions on approximately 12-hour timescales.

Although the term improves the qualitative agreement between the model and the measurements, the paper does not provide a specific physical justification for this nonlinear depletion process. Establishing such a mechanism would strengthen the physical interpretation and predictive credibility of the proposed model.

References

The absence of a corresponding overshoot during step-down transitions suggests that this process depends primarily on the final exposure level rather than the transition magnitude $|I_0-I_f|$. This assumption is consistent with the experimental data, however, we are not aware of a specific physical motivation for this nonlinear depletion trap.

— Measuring and Modelling Lag in Amorphous Silicon Flat-Panel X-ray Detectors  (2608.26542 - Huang et al., 27 Aug 2026) in Proposed modifications to rate equations, Section 6.1, Model