Does reverse bias IV characteristics of diode depend on signal frequency?

Question

I've performed an experiment with oscilloscope, applying 10V P-P sine wave and then plotting the voltage across resistor (current) and voltage across diode (voltage) in XY mode of the oscilloscope. The IV curve in 100Hz was quite different than the IV curve in 5000Hz. Any theoretical explanations.

Answer 1

The previous answer is correct.
If you check all the parameters and characteristics of the diode you are using in your scope observations - you will see a limiting frequency parameter. This is due both to the capacitance and the actual switching speed (turn on / turn off times) of the jucntion. Both parameters will muddle up your expected results of the scope patterns.
At very high frequencies, a general purpose AC rectifier diode may well show little or no half wave rectification at all due to the shunt capacitance and speed cross its junction - yet it will check fine out of the circuit.
Capacitance can be a strange phenomenon when you least expect it - often, it has to be accounted for in formulas and circuits even when purely inductive and linear components are used. It can raise havoc at high frequencies simply because the interconnecting wires are poorly routed - or too many are routed parallel to each other.
Try a different diode with a little more forgiveness on the frequencies you're using in your tests.

Answer 2

Another answer after me can correct me if I am wrong, since solid-state devices are not my best area in electrical engineering.

But, I recall that a reverse-biased p-n junction (a diode) acts like a capacitor. Thus, the reverse biased diode would have a different impedance at the two different sine-wave frequencies and thus differing IV characteristics.

Check out the datasheet for your diode, and check for a parameter like "reverse-bias capacitance" or something of that nature.