Which characteristic of a Schottky diode makes it a better choice than a silicon junction diode for use as a power supply rectifier?
Why A Schottky diode uses a metal-to-semiconductor junction instead of a P-N junction, so it conducts at roughly 0.2 to 0.3 volts instead of the 0.7 volts typical of silicon. In a rectifier the dissipated power is that forward drop times the load current, so cutting the drop by half a volt means less heat and better supply efficiency, which matters most in high-current, low-voltage supplies. Schottkys also switch fast because they have essentially no minority carrier storage, which helps in switching power supplies.
Watch out The reverse breakdown claim is backwards: Schottky diodes generally have lower reverse voltage ratings than comparable silicon junction diodes, and a constant reverse avalanche voltage describes a Zener. Long carrier retention is also the opposite of the Schottky's near-zero reverse recovery time.
Schottky = short drop: about 0.3 V instead of 0.7 V, so less heat in the rectifier.