Diodes

Diode - the simplest semiconductor device

The most common function of a diode is to rectify current - allowing it to pass in only one direction (called the conduction direction), while blocking it in the opposite direction (reverse bias). However, diodes can have more complex behavior than just controlling current flow, due to their nonlinear current-voltage (I/V) characteristics. Semiconductor diodes begin to conduct electricity only when the threshold voltage in the conduction direction is reached. The voltage drop across the diode varies only with temperature; this effect can be used to measure it.

Different types of diodes

The I/V characteristics of the diode can be changed by selecting appropriate materials. These techniques are used to create special purpose diodes for example for voltage stabilization ( Zener diodes ), for protecting circuits against voltage spikes ( avalanche and Schottky diodes ), for electronic tuning of radio and television receivers ( varicaps and varactors ), for generating RF oscillations ( tunnel diodes, Gunn diodes ) to produce light ( LEDs ). Diodes, both vacuum and semiconductor, can be used as shot noise generators.

The history of the diode

Thermionic diodes (vacuum or gas-filled) and semiconductor diodes were developed separately but at about the same time in the early 20th century, first as detectors for radio receivers. By the 1950s, vacuum diodes were more commonly used because early semiconductor blade diodes were unstable. Additionally, most receiver sets already had other vacuum tubes for amplification, so diodes could be easily integrated into these components. Tube rectifiers - vacuum and gas - were able to handle high currents and voltages better than semiconductor diodes (such as selenium rectifiers) that were available at the time. It was only in the 1950s that junction diodes were developed - using a semiconductor PN junction - and slowly began to replace tube devices.

Principle of operation of the PN junction

A PN junction is formed at the interface between two semiconductor materials with P and N doping. The P side contains an excess of holes and the N side contains excess electrons. This allows electric current to flow through the junction in only one direction when an external electric field - voltage - is applied to the semiconductor device. The PN junction is formed by doping layers, for example by ion implantation, dopant diffusion or epitaxy.

Types of diodes

Our store offers a wide selection of semiconductor diodes, dedicated to many applications. In addition to typical current rectification devices, we offer elements such as Schottky diodes or Zener diodes, characterized by an unusual shape of the I/V curve, and light-emitting diodes, which emit light under the influence of electric current. Each of these semiconductor devices is dedicated to a different application. Thanks to the clear division into categories in the Botland store, you will easily find the item you need.