V-I Characteristics of Diode

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V-I Characteristics of Diode

on June 25, 2013

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What Are Diodes Made Out Of?

What Are Diodes Made Out Of? Silicon (Si) and Germanium (Ge) are the two most common single elements that are used to make Diodes. A compound that is commonly used is Gallium Arsenide (GaAs), especially in the case of LEDs because of it’s large band gap. The diagram above shows the 2D structure of the Si crystal. The light green lines represent the electronic bonds made when the valence electrons are shared. Each Si atom shares one electron with each of its four closest neighbors so that its valence band will have a full 8 electrons. Silicon and Germanium are both group 4 elements, meaning they have 4 valence electrons. Their structure allows them to grow in a shape called the diamond lattice. Gallium is a group 3 element while Arsenide is a group 5 element. When put together as a compound, GaAs creates a zincblend lattice structure. In both the diamond lattice and zincblend lattice, each atom shares its valence electrons with its four closest

The Biased PN Junction

The Biased PN Junction The pn junction is considered biased when an external voltage is applied. There are two types of biasing: Forward bias and Reverse bias. Forward Bias ( V(applied) > 0 ) : In forward bias the depletion region shrinks slightly in width. With this shrinking the energy required for charge carriers to cross the depletion region decreases exponentially. Therefore, as the applied voltage increases, current starts to flow across the junction. The barrier potential of the diode is the voltage at which appreciable current starts to flow through the diode. The barrier potential varies for different materials. Reverse Bias ( V(applied) < 0 ) : Reverse Bias: Under reverse bias the depletion region widens. This causes the electric field produced by the ions to cancel out the applied reverse bias voltage. A small leakage current, Is (saturation current) flows under reverse bias conditions.This saturation current is made up of electr

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V-I Characteristics of Diode

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