Explain vi characteristics of pn junction diode

An ideal diode means a perfect diode which has all properties in their perfect sense without any flaws. Usually, a diode operates either in forward or reverse biased condition. The characteristics which are expected to be exhibited by the ideal diode can be analyzed separately for these two modes of operation. Characteristics of Ideal Diode when Forward Biased Zero Resistance An ideal diode does not offer any resistance to the flow of Infinite Amount of Current This property of the ideal diode can be directly implied from its previous property which states that the ideal diodes offer zero resistance when forward biased. The reason can be explained as follows. In electronic devices, the relationship between the current (I), Zero Threshold Voltage Even this characteristic of the ideal diode under the forward biased state can be referred from its first property of possessing zero resistance. This is because threshold voltage is the minimum voltage which is required to be provided to the diode to overcome its barrier potential and to start conducting. Now, if the ideal diode is void of depletion region itself, then the question of threshold voltage does not arise at all. This property of the ideal diode makes them conduct right at the instant of being biased, leading to the green-curve of Figure 1 which shows the diode characteristics. Characteristics of Ideal Diode when Reverse Biased Infinite Resistance An ideal diode is expected to fully inhibit the flow of current through ...

Avalanche breakdown is a phenomenon observed in a p-n junction diode in reverse bias. When a large reverse bias voltage is applied across a p-n junction diode, thermal current starts increasing to a large value. This results in the heating of the diode. Some avalanche diodes are used as voltage regulators similar to zener diodes. Dynamic resistance Dynamic resistance is used to quantify the resistance of non-ohmic materials. It is defined as the ratio of differential change in voltage to a differential change in current. r = d I d V ​ Note: Dynamic resistance is itself a function of the current (or voltage) through the material for a non-ohmic conductor. In a p-n junction diode, the current I can be expressed as I = I 0 ​ e x p ( 2 K B ​ T e V ​ − 1 ), where I 0 ​ is called the reverse saturation current, V is the voltage across the diode and is positive for forward bias and negative for reverse bias, and I is the current through the diode, k B ​ is the Boltzmann constant ( 8 . 6 × 1 0 − 5 e V / K ) and T is the absolute temperature. If for a given diode I o ​ = 5 × 1 0 − 1 2 A and T = 3 0 0 K, then (a) What will be the forward current at a forward voltage of 0 . 6 V?(b) What will be the increase in the current if the voltage across the diode is increased to 0 . 7 V?(c) What is the dynamic resistance?(d) What will be the current if reverse bias voltage changes from 1 V to 2 V? Draw the circuit arrangement for studying the V-I characteristics of a p-n junction diode (i) in ...

Semiconductors can be doped with other materials to become p-type or n-type. A p-n junction diode can be forward or reverse bias. LEDs are forward bias diodes that produce photons of light. Solar cells are p-n junctions that absorb photons, giving electrons enough energy to enter the conduction band. Semiconductor p-n junction diode A p-n junction diode is formed by doping one half of the semiconductor crystal with p-type impurity and the other half with n-type impurity while the crystal is being formed. Unbiased p-n junction Unbiased conditions mean that there is no external energy source (no voltage). In an unbiased diode, an electric field is set up across the depletion layer between the n-type and the p-type material. This is caused by the imbalance in free electrons due to the doping. Reverse biased diode In reverse bias the diode is connected with the p-type connected to the negative supply terminal and the n-type connected to the positive. The electric field across the depletion layer increases. This acts as a barrier that stops electron flow. The valence band energy level in the p-type material is raised above the free electrons of the conduction band of the n-type. This is due to the combination of doping and electric field across the junction. Forward biased diode In forward bias , electrons in the conduction band of the n-type move towards the conduction band of the p-type. Electrons drop from the conduction band to valence band of the p-type semiconductor. This...