base
when the p-n junction is heavily doped p-n junction diode has very sharp breakdown voltage.
Emitter is heavily doped because to provide charge carriers to Base & Collector region, Base and Collectors are lightly doped because to accept those charge carriers.
No, a functioning junction diode cannot be made by placing two oppositely doped pieces of semiconductor in contact with each other. A functioning junction diode can only be created in one piece of semiconductor with oppositely doped regions in it.However if you placed the two oppositely doped pieces of semiconductor in contact with each other and HEATED them until they just began to melt and joined becoming one piece, it is possible to create a functioning junction diode this way. But this is a tricky and not very reliable way to do it, especially if you melt it just a tiny bit too much you will completely mix the two pieces and lose the doping entirely.
3: emitter, base, collectorThere are three regions but to be absolutely picky I think only two of them need be doped.Nope: they MUST be doped NPN or PNP. If any are undoped it will not function as a transistor.
base
Zener diode is heavily doped pn junction diode.
when the p-n junction is heavily doped p-n junction diode has very sharp breakdown voltage.
A Gunn diode, also known as a transferred electron device (TED), is a form of diode used in high-frequency electronics. It is somewhat unusual in that it consists only of N-doped semiconductor material, whereas most diodes consist of both P and N-doped regions. In the Gunn diode, three regions exist: two of them are heavily N-doped on each terminal, with a thin layer of lightly doped material in between. When a voltage is applied to the device, the electrical gradient will be largest across the thin middle layer. Conduction will take place as in any conductive material with current being proportional to the applied voltage. Eventually, at higher field values, the conductive properties of the middle layer will be altered, increasing its resistivity and reducing the gradient across it, preventing further conduction and current actually starts to fall down. In practice, this means a Gunn diode has a region of negative differential resistance.
it will increase
A Gunn diode, also known as a transferred electron device (TED), is a form of diode, a semiconductor electronic component, used in high-frequency electronics. Its internal construction is unlike other diodes in that it consists only of N-doped semiconductor material, whereas most diodes consist of both P and N-doped regions. In the Gunn diode, three regions exist: two of them are heavily N-doped on each terminal, with a thin layer of lightly doped material in between. When a voltage is applied to the device, the electrical gradient will be largest across the thin middle layer. Conduction will take place as in any conductive material with current being proportional to the applied voltage. Eventually, at higher field values, the conductive properties of the middle layer will be altered, increasing its resistivity, preventing further conduction and current starts to fall. This means a Gunn diode has a region of negative differential resistance. Its largest use is in electronic oscillators to generate microwaves, in applications such as radar speed guns and microwave relay transmitters
Emitter is heavily doped because to provide charge carriers to Base & Collector region, Base and Collectors are lightly doped because to accept those charge carriers.
Zener diodes are heavily doped to create a narrow depletion region, allowing them to operate in the reverse breakdown region where they exhibit the Zener effect. This effect causes the diode to conduct in reverse bias at a specific voltage, ideal for voltage regulation applications.
because that the tunnel diode is a standard pn junction diode in many respect except its highly doped pn junction so it has some characteristics in the negative resistance region another that its a standard diode
LED is short for Light Emitting Diode. It is a special type of diode that emits light when it is forward biased. Diodes are made using N doped and P doped semiconductors(not intrinsic/pure.) They form a junction that allows the system to act as a diode. So in short, no. However these doped semiconductors were made using pure(intrinsic) semiconductors. Therefore depending on how far you trace back the process the semiconductors were once intrinsic. So depending on how you look at it, yes.
No, a functioning junction diode cannot be made by placing two oppositely doped pieces of semiconductor in contact with each other. A functioning junction diode can only be created in one piece of semiconductor with oppositely doped regions in it.However if you placed the two oppositely doped pieces of semiconductor in contact with each other and HEATED them until they just began to melt and joined becoming one piece, it is possible to create a functioning junction diode this way. But this is a tricky and not very reliable way to do it, especially if you melt it just a tiny bit too much you will completely mix the two pieces and lose the doping entirely.
3: emitter, base, collectorThere are three regions but to be absolutely picky I think only two of them need be doped.Nope: they MUST be doped NPN or PNP. If any are undoped it will not function as a transistor.