What is rectifying contact in semiconductor?
What is rectifying contact in semiconductor?
When a metal and a semiconductor are joined, two possible types of contact can result, depending on the combination of metal and semiconductor used. The contact may be rectifying, which only allows current to pass in one direction. Alternatively, it could be ohmic, in which case current can pass in either direction.
What are rectifying contacts?
A rectifying contact is similar to a pn junction inasmuch as it allows a large current in one voltage polarity and a much smaller current in the other. A contact is said to be ohmic, i.e., non-rectifying, if it exhibits negligible resistance to current in both voltage polarities.
What is a rectifying junction?
The rectifying metal semiconductor junction is also known as a Schottky Diode. When a metal is in close contact with a semiconductor, the semiconductor becomes depleted of its carriers near the interface, exhibits a “Schottky barrier” much higher than thermal energy kT, we call it a rectifying junction.
Under which situation we can have rectifying metal semiconductor contact?
Conclusion. Overall, for a metal and an n-type semiconductor, a rectifying Schottky contact is formed when ΦM>ΦS, and an Ohmic contact is formed when ΦM<ΦS. Similarly, for a metal and an p-type semiconductor, the MS contact will be rectifying Schottky when ΦM<ΦS, and Ohmic contact when ΦM>ΦS.
What is non rectifying contact?
The Ohmic contact is a low resistance junction (non-rectifying) provides current conduction from metal to semiconductor and vice versa. Theoretically speaking the current should increase/ decrease linearly with the applied voltage. With an immediate response for the any small voltage.
What is heterojunction in semiconductor?
From Wikipedia, the free encyclopedia. A heterojunction is an interface between two layers or regions of dissimilar semiconductors. These semiconducting materials have unequal band gaps as opposed to a homojunction.
What do you mean by ohmic and rectifying metal semiconductor junction?
M–S junctions can either be rectifying or non-rectifying. The rectifying metal–semiconductor junction forms a Schottky barrier, making a device known as a Schottky diode, while the non-rectifying junction is called an ohmic contact.
What does it mean rectifying?
transitive verb. 1 : to set right : remedy. 2 : to purify especially by repeated or fractional distillation rectified alcohol. 3 : to correct by removing errors : adjust rectify the calendar.
What is rectifying and non rectifying contact?
The rectifying metal–semiconductor junction forms a Schottky barrier, making a device known as a Schottky diode, while the non-rectifying junction is called an ohmic contact. (In contrast, a rectifying semiconductor–semiconductor junction, the most common semiconductor device today, is known as a p–n junction.)
What does non-rectifying mean?
“non-rectifying junction” = connection where current can flow the same in both directions. If contact between different types of materials there can be a rectifying junction (like a galena cats-whisker crystal diode). A diode does not allow current to flow the same in both directions.
What are Schottky contacts?
The rectifying contact that occur between a metal and a lightly doped semiconductor. b) Ideal energy -band diagram of a metal and n-type semiconductor junction. …
What is homojunction and heterojunction?
In a simplest deffinition, a homojunction is a junction between the same materials with the same crystalline structure. A heterojunction is a junction between different materials or between the same materials, but with different crystal structure.
What makes a metal-semiconductor contact look ohmic?
(They obey Ohm’s Law).There are two ways to make a metal-semiconductor contact look ohmic enough to get signals into and out of a semiconductor (or doing the opposite makes a good Schottky contact). The barrier height is a property of the materials we use. We try to use materials whose barrier height is small.
Why do we need ohmic and Schottky contacts?
Almost all metal-semiconductor junctions will exhibit some of this rectifying behavior.Schottky Contacts make good diodes, and can even be used to make a kind of transistor, but for getting signals into and out of a semiconductor device, we generally want a contact that is Ohmic. Ohmic contacts conduct the same for both polarities.
What happens when a metal and a semiconductor are joined?
When a metal and a semiconductor are joined, two possible types of contact can result, depending on the combination of metal and semiconductor used. The contact may be rectifying, which only allows current to pass in one direction. Alternatively, it could be ohmic, in which case current can pass in either direction.
What is contact resistance in an ohmic interface?
Contact resistance is a measure of the ease with which current can flow across a metal-semiconductor interface. In an ohmic interface, the total current density J entering the interfaceis a function of the difference in the equilibrium Fermi levels on the two sides.
