Diodes have 2 slowness mechanisms which can be harmful in switching applications
Junction capacitance with reverse voltage. It takes some time to charge it to the reverse voltage, so the current flows to the reverse direction. The capacitance decreases as the reverse voltage grows so it needs either advanced simulation or a test circuit to see the effect exactly. The effect exists as well in PN diodes and Schottky diodes.
In PN diodes the current flows well also to the reverse direction until the minority carriers have vanished by recombinating.
The recombination doesn't in all cases seem to effectively start as soon as the voltage is reversed. High current rectifier diodes conduct to the reverse direction a substantially long time before the current starts to decay visibly. The full reverse conductivity time is in datasheets "Storage Time". After the storage has elapsed the current decays with time constant "Reverse Recovery Time" towards the final leakage value.
See this tutorial: https://www.tutorialspoint.com/electronic_circuits/electronic_circuits_diode_as_switch.htm
Reverse conductivity after a forward current isn't in all cases considered as slowness. For microwave applications we have "Snap diodes" which conduct intentionally some time to the reverse direction. But the reverse recovery happens after the storage time so fast that the current contains powerful high frequency distortion components. With a proper resonator we can extract a substantial microwave power at a frequency which is a multiple of our original signal frequency. "Frequency multipliers" can be constructed with this idea.