A diode using this property is called a Zener diode. It can be used to regulate the voltage in a circuit. Semiconductor diodes can be designed to have different characteristics.
A varactor diode has a capacitance that is dependent upon the voltage across it.
In another kind, the tunnel diode, the current through the device decreases as the voltage is increased within a certain range. This is called negative resistance and it is useful as an amplifier.
Light-sensitive or photosensitive diodes can be used to measure illumination as the voltage drop across them depends on the amount of light that they are exposed to. These are similar but not the same as LDR’s (light dependant resistors).
A light-emitting diode produces light as current passes through it. Some LED's can act as the light source of lasers.
A perfect diode would be able to take any voltage but in the diodes we have today, when the voltage applied in the reverse direction exceeds a certain value, a semiconductor diode breaks down and conducts heavily in the direction of normally high resistance. This normally happens at around 400v.
Also a perfect diode would turn on the instant that any voltage is applied not 0.6v as the diodes we have at the moment turn on.
If they turned on and off as I have said above they would be much more efficient and more useful for the person using them.
I think that that as technology advances in the future diodes will get closer to being a perfect diode.