How do you calculate built-in potential?
The built-in potential (at 300 K) equals fi = kT/q ln(1016 x 9 x 1017/ni2) = 0.77 V, using kT/q = 25.84 mV and ni = 1010 cm-3. The built-in potential (at 100°C) equals fi = kT/q ln(1016 x 9 x 1017/ni2) = 0.673 V, using kT/q = 32.14 mV and ni = 8.55 x 1011 cm-3 (from Example 20).
What is the value of potential barrier voltage for germanium pn junction?
approximately 0.3 V
What will be the potential barrier for Si diode?
Typically at room temperature the voltage across the depletion layer for silicon is about 0.6 – 0.7 volts and for germanium is about 0.3 – 0.35 volts. This potential barrier will always exist even if the device is not connected to any external power source, as seen in diodes.
Why do we use zener diode?
Zener diodes are used for voltage regulation, as reference elements, surge suppressors, and in switching applications and clipper circuits. The load voltage equals breakdown voltage VZ of the diode. The series resistor limits the current through the diode and drops the excess voltage when the diode is conducting.
What causes depletion region?
The depletion region is caused by the diffusion of charges. The holes and the electrons diffusing towards each other combine near the junction. In doing so positive and negative ions are formed. The pair of positive and negative ions at the junction forms the dipole.
How does the depletion region behave?
In the depletion region, an electric field exists that quickly sweeps out electron-hole pairs that may be thermally generated and reduces the equilibrium concentration of the charge carriers to exceedingly low levels. This region, called the depletion layer, behaves as an insulator.
What happens in depletion region?
Depletion Region Details Filling a hole makes a negative ion and leaves behind a positive ion on the n-side. A space charge builds up, creating a depletion region which inhibits any further electron transfer unless it is helped by putting a forward bias on the junction.
What do you understand by depletion region?
In semiconductor physics, the depletion region, also called depletion layer, depletion zone, junction region, space charge region or space charge layer, is an insulating region within a conductive, doped semiconductor material where the mobile charge carriers have been diffused away, or have been forced away by an …
What is the width of depletion region?
The physical width of the depletion region in a typical Si diode ranges from a fraction of a micrometer to tens of micrometers depending on device geometry, doping profile, and external bias. Figure 11.4.
What is difference between potential barrier and depletion region?
Deplection region is a region created around the p-n junction which is devoid of free charge carriers and has immobile ions. Potential barrier is a potential difference or junction voltage developed across the junction due to migration of majority carriers across it when p-n junction is formed.
How is pn junction formed?
P-n junctions are formed by joining n-type and p-type semiconductor materials, as shown below. However, in a p-n junction, when the electrons and holes move to the other side of the junction, they leave behind exposed charges on dopant atom sites, which are fixed in the crystal lattice and are unable to move.
What is potential barrier in pn junction?
Definition: The potential barrier in the PN-junction diode is the barrier in which the charge requires additional force for crossing the region. In other words, the barrier in which the charge carrier stopped by the obstructive force is known as the potential barrier.
Why pn junction is called diode?
Learn It! Diodes allow current flow in one direction but not the other. A diode is called a diode because it has two distinct electrodes (i.e. terminals), called the anode and the cathode. A diode is electrically asymmetric because current can flow freely from the anode to the cathode, but not in the other direction.
What is the main function of PN diode?
A p-n junction diode is a basic semiconductor device that controls the flow of electric current in a circuit. It has a positive (p) side and a negative (n) side created by adding impurities to each side of a silicon semiconductor.
Why it is called diode?
A diode is called a diode because it has two distinct electrodes (i.e. terminals), called the anode and the cathode. A diode is electrically asymmetric because current can flow freely from the anode to the cathode, but not in the other direction. In this way, it functions as a one-way valve for current.
What is the use of PN junction diode?
PN junction diode is a diode which can be used as a rectifier, logic gate, voltage stabiliser, switching device, voltage dependent capacitor and in optoelectronics as a photodiode, light-emitting diode (LED), laser diode, photo detector, or solar cell in electronics.
What is the application of a diode?
The application areas of diodes include communication systems as limiters, clippers, gates; computer systems as logic gates, clampers; power supply systems as rectifiers and inverters; television systems as phase detectors, limiters, clampers; radar circuits as gain control circuits, parameter amplifiers, etc.
What is the principle of pn junction diode?
A pn junction diode is a two terminal single crystal semiconductor device whose one side is doped with acceptors and other side by donors. Doping with acceptor creates p type semiconductor while doping with donors produces n type. Thus a pn junction is formed in diode.
What is the working principle of diode?
The most common function of a diode is to allow an electric current to pass in one direction (called the diode’s forward direction), while blocking it in the opposite direction (the reverse direction). As such, the diode can be viewed as an electronic version of a check valve.
Does diode convert AC to DC?
The term rectifier describes a diode that is being used to convert AC to DC. Most rectifier circuits contain a number of diodes in a specific arrangement to more efficiently convert AC power to DC power than is possible with only a single diode.
What is the symbol of diode?
Diode, an electrical component that allows the flow of current in only one direction. In circuit diagrams, a diode is represented by a triangle with a line across one vertex.
How does a diode behave in a circuit?
Current passing through a diode can only go in one direction, called the forward direction. Current trying to flow the reverse direction is blocked. They’re like the one-way valve of electronics. If the voltage across a diode is negative, no current can flow*, and the ideal diode looks like an open circuit.
What happens if a diode is reversed?
Reverse bias usually refers to how a diode is used in a circuit. If a diode is reverse biased, the voltage at the cathode is higher than that at the anode. Therefore, no current will flow until the electric field is so high that the diode breaks down.
What is the reverse voltage of a diode?
The reverse voltage is the voltage drop across the diode if the voltage at the cathode is more positive than the voltage at the anode (if you connect + to the cathode). This is usually much higher than the forward voltage. As with forward voltage, a current will flow if the connected voltage exceeds this value.
How much current can a diode handle?
Forward Current The maximum that the diode can conduct at once is 30 amperes. However; if the diode is required to conduct that much current at once, the diode will fail in approximately 8.3 milliseconds.
Do diodes reduce voltage?
After each diode, the voltage can be seen to drop by 0.6 volts. In this way, diodes can be used to reduce voltage, in a circuit. Zener diodes allow electricity to flow through them, in the same way as normal diodes.
Do diodes increase voltage?
As we know from the i-v curve, the current through and voltage across a diode are interdependent. Once the voltage gets to about the forward voltage rating, though, large increases in current should still only mean a very small increase in voltage.