1) the reverse current of the silicon diode is much smaller than that of the germanium diode. The germanium tube is the mA class and the silicon tube is the nA level. This Is because in the same temperature ge ni Is about three orders of magnitude higher than the silicon ni, so under the same doping concentration of silicon Jane concentrations less than Jane of germanium concentration, so the silicon tube reverse saturation current Is very small.
2) when the forward voltage is very small, the current of the diode is very small, and only after the forward voltage reaches a certain number Ur, the current will increase significantly. Normally the voltage Ur is called a diode threshold voltage, also known as a dead zone voltage or threshold voltage. The threshold voltage of a silicon diode Is greater than the threshold voltage of the germanium diode because the Is of the silicon diode Is far smaller than that of the germanium diode. The threshold voltage of general silicon diode is about 0.5v ~ 0.6v, and the threshold voltage of germanium diode is about 0.1v ~ 0.2v.