# Determine material of Zener's diode based on its characteristics

I have a plot log (I) = f(U) for a few diodes: Silicon diode, Germanium diode, some LED and a Zener diode. I need to determine the material, from which the Zener diode is made based on the positioning of its characteristics. What parameter should I look for to determine it? I thought about checking the band gap somehow, but I am not sure whether it can be determined by just having a plot log(I) = f(U).

And if I know the difference between voltages (for specified current) of two diodes , let's call them A and B, and I have some information about diode A (including its band gap), can I calculate the band gap of the B diode?

• The material is Silicon not silicone Nov 18 '13 at 16:30

I'm not sure if I understand your problem, but if you want to determine which of the four types of diodes you have you can look at the forward voltage (V_f) and reverse voltage when diode starts to conduct at reverse polarity (V_r) and maybe reverse leakage current (I_rl) before that point:
• Si-Diode: V_f ca. 0.6 V, large V_r, low Irl
• Ge-Diode: V_f ca. 0.3V, relative large I_rl
• LED: relative large V_f (> 1V, e.g. 1.4 V, depending on material)
• Si-Zener-Diode: V_f ca. 0.6V, V_r = V_zener