a diode in which a metal and a semiconductor form a pn junction

a majority carrier device, where electron-hole recombination is usually not important

a metal-semiconductor junction (rather than a junction between two semiconductor materials), but you don't need to know that

a special type of diode with a very low forward-voltage drop

hot carrier diode. A diode using an aluminium-silicon junction in which carrier storage is negligible, leading to very fast on and off states and thus very fast switching speeds. The foward voltages is 0.3v.

This is a type of diode that features a fast recovery time and a low forward voltage drop (0.6V). If a diode is needed for a high current, low voltage supply (5v DC) and when low losses and high speed are important, a schottky diode can be used with great success.

a diode formed by contact between a metal and a semiconductor.

A type of diode, used to rectify alternating current into direct current.

A junction or barrier formed by the direct contact of semiconductor materials with a metal. This type of contact rectifies signals and may also exhibit some resistance.

High speed diode that has very little junction capacitance. Also known as a "hot-carrier diode" or a "surface-barrier diode."

An ultra-fast diode with very little junction capacitance.

The Schottky diode (named after German physicist Walter H. Schottky; also known as hot carrier diode) is a semiconductor diode with a low forward voltage drop and a very fast switching action. Typical applications include discharge-protection for solar cells connected to lead-acid batteries and in switch mode power supplies; in both cases the low forward voltage leads to increased efficiency.