On the entropy and exponential convergence to equilibrium for the recombination-drift-diffusion system for scintillators

For the recombination-drift-diffusion equations that describe the evolution of charge carriers in scintillating crystals, we obtain the estimates for the energy and solution asymptotic decay. Our results extend those obtained by Fellner and Kniely (2018) for semiconductors with two charge carriers and Shockley–Hall recombination, to the case of k>2 charge carriers and a general polynomial recombination term.