Energy band diagram of pn junction diode in forward bias

To reversebias the pn junction, the p side is made more negative, making it uphill for electrons moving across the junction. We now consider a pn diode with an applied bias voltage, va. As we increase the applied volatge the drop across the nuentral region increases such that the n side depletion region is always higher in potential to the p side depletion region. An energy diagram for a pn junction at the instant of formation is shown in figure a. Energyband diagram of forwardbiased pn junction physics stack. Animation how a p n junction semiconductor works forward reverse bias diffusion. Draw the energy band diagram of pn junction diode in forward and.

In this video, i go over the band diagram of the pn junction, which will allow. The upward direction in the diagram represents increasing electron energy. Energy band diagram of a pn junction a before and b after merging the ntype and ptype regions note that this does not automatically align the fermi energies, e f,n and e f,p. For the love of physics walter lewin may 16, 2011 duration. Smith department of eecs university of california, berkeley eecs 105 spring 2004, lecture 19 prof. The energy band diagram of the pnjunction duration. The fermi levels vary when the diode is unbiased as well as it is forward biased or reverse biased. Energy bands are affected based on the biasing techniques applied. Pn junction operation in forwardbias mode, showing reducing depletion width. Electronicpn junction diode forward biasreverse bias.

The valence and conduction bands in an ntype material are at slightly lower energy levels than the valence. Sketch the energy band diagram of an abrupt pn junction under zero bias in which the p region is degenerately doped and e c e f in the n region. Forward biasing increases the electron density in the conduction band of the n side. In this video, i go over the band diagram of the pn junction, which will.

Energy band diagram of a pn junction under reverse. Applying forward bias to the pn junction diode causes a low impedance path for the junction diode, allows for conducting a large amount of current known as infinite current. Band diagram of pn junction under a equilibrium and b forward bias. The panels show energy band diagram, electric field, and net charge density. In forward bias, the ptype is connected with the positive terminal and the. In each case, the graph is known as the forward characteristic of the junction. The depletion width shrinks in forward bias and expands in reverse bias. For normal pn junction diode, fermi level will shift upward in nside with respect to pside if bias voltage is applied in forward direction, i. They readily combine with those holes, making possible a continuous forward current through the junction. What happens to the fermi level after we apply a bias. If the reverse voltage applied is above this breakdown voltage, the apd will operate in its geigermode. Pn junction forward bias forward bias characteristics. When the diode is unbiased the state of the junction will be at equilibrium.

When the pn junction is forward biased, the electrons in the ntype material which have been elevated to the conduction band and which have diffused across the junction find themselves at a higher energy than the holes in the ptype material. Pn junction diode explained forward bias and reverse bias duration. Review, pn junctions, fermi levels, forward bias prof j. Band diagram of the reversebiased p n junction diode with the. Also, note that this flatband diagram is not an equilibrium diagram since both electrons and holes can lower their energy by crossing the junction. E is the electron emission energy for the conductionband well. The energy band information is summarized in figure 10. The value of forward current is directly proportional to the external power supply and inversely proportional to the internal resistance of the junction diode. As we increase the applied volatge the drop across the nuentral region increases such that the n side depletion region is. Download scientific diagram pn junction with reversed bias. Draw the energy band diagram of an unbiased pn junction and mark the barrier potential and depletion region. It is seen that very little forward current flows until v f exceeds the junction barrier, voltage 0. In this lecture, i discussed about the energy band diagram of the pn junction in equilibrium.