Contents
- 1 How do you graph a forward bias?
- 2 Does recombination occur in depletion region?
- 3 What is the difference between forward and reverse bias?
- 4 What is the effect of forward bias on a PN junction?
- 5 How is the rate of recombination related to the total current?
- 6 How does forward bias affect the p-n junction?
How do you graph a forward bias?
For forward-bias
- Make circuit diagram as shown in diagram.
- Make all connections neat, clean and tight.
- Note least count and zero error of voltmeter (V) and milli-ammeter (mA).
- Bring moving contact of potential divider (rheostat) near negative end and insert the key K.
Does recombination occur in depletion region?
The current in a p-n diode is due to carrier recombination or generation somewhere within the p-n diode structure. Under forward bias, the diode current is due to recombination. This recombination can occur within the quasi-neutral regions, within the depletion region or at the metal-semiconductor Ohmic contacts.
What happens to the depletion region during forward bias?
Forward bias (applying a positive voltage to the P-side with respect to the N-side) narrows the depletion region and lowers the barrier to carrier injection (shown in the figure to the right). The more bias the more neutralization (or screening of ions in the region) occurs.
When PN junction is forward biased then depletion region?
the depletion region is reduced and barrier height is increased.
What is the difference between forward and reverse bias?
A reverse bias strengthens the potential barrier, whereas a forward bias diminishes the potential barrier of the electric field across the potential. A reverse bias has an anode voltage that is less than its cathode voltage. In contrast, a forward bias has an anode voltage that is greater than the cathode voltage.
What is the effect of forward bias on a PN junction?
When a p-n junction is forward biased, the built-in electric field and the applied electric field are in opposite directions. When both the electric fields are added then the resultant electric field is lesser than the built-in electric field. This results in the build up of thinner and less resistive depletion region.
When a PN junction is forward biased the sequence of process that takes place is?
When the PN junction is forward biased the sequence of events that take place are : a. Diffusion, drift and recombination.
How are minority carriers supplied in a forward bias?
So far we have assumed that, under a forward bias, the minority carriers diffusing and recombining in the neutral regions are supplied by the external current. However, some of the minority carriers will recombine in the depletion region. The external current must therefore also supply the carriers lost in the recombination process in the SCL.
The rate at which the electrons in ABC are recombining is the area ABC (nearly all injected electrons) divided by re. The electrons are replenished by the diode current. Similarly, the rate at which holes in BCD are recombining is the area BCD divided by rh.
How does forward bias affect the p-n junction?
When we apply forward bias (positive voltage to p-type, negative voltage to n-type) it effectively reduces the built-in voltage. When we apply reverse bias (positive voltage to n-type, negative voltage to p-type) it effectively increases the built-in voltage.
What is the hole concentration in reverse bias?
Assume that the reverse bias Vr > kT/e = 25 mV. The hole concentration Pn (0) just outside the SCL is nearly zero by the law of the junction, Equation 6.9, whereas the hole concentration in the bulk (or near the negative terminal) is the equilibrium concentration pno, which is small.