What is the mixing diode
The mixing diode is a Schottky barrier diode. Compared with the general diode, it has the characteristics of high frequency, low noise and small reverse current due to the use of majority carriers and no minority carrier storage effect. Mainly used for mixers.
The mixing diode is made by using a metal formed by contact between a metal and an n-type semiconductor. When the metal is in contact with the semiconductor, a Schottky barrier that blocks the passage of electrons, that is, a surface barrier, is formed at their interface. In order for a carrier in a semiconductor to easily cross the barrier into the metal, it must employ an n-type semiconductor that has a much larger electron work function (the energy required to run out of the semiconductor or metal surface) than the metal. When the diode is forward biased, the barrier drops and most of the carriers (electrons) enter the metal from the semiconductor.