From UPSC perspective, the following things are important :
Prelims level : HEMT
Mains level : NA
Indian Scientists from Bangalore have developed a highly reliable, High Electron Mobility Transistor (HEMTs) that is normally OFF the device and can switch currents up to 4A and operates at 600V.
We cannot deny the possibility of a complex S&T based prelims question. This newscard seems very technical. However many of you might be aware of the p-n junction diodes and conventional transistors.
What is HEMT?
- A high electron mobility transistor or HEMT is a type of field-effect transistor (FET) that is used to produce a high performance at microwave frequencies.
- The HEMT provides a fusion of low noise figure that comes combined with the unique ability to function at very high microwave frequencies.
- These devices are commonly used in aspects of radiofrequency designs that require high performance at high-frequency levels.
- They produce a high gain, which makes these transistors very useful as amplifiers. They can switch speeds very rapidly.
- And finally, they produce very low noise values as the current variations in these transistors are comparatively low.
Practical applications of HEMT
- HEMTs are used in applications where microwave millimetre wave communications are conducted.
- They are also used for radar, imaging, as well as radio astronomy.
- They are also used in voltage converter applications.
- These transistors are also ideal as digital on-off switches in integrated circuits, and to be used as amplifiers for huge amounts of current by using a small voltage as a control signal.
What is the news?
First-ever indigenous HEMT
- This first-ever indigenous HEMT device made from gallium nitride (GaN) is useful in electric cars, locomotives, power transmission and other areas requiring high voltage and high-frequency switching.
- It would reduce the cost of importing such stable and efficient transistors required in power electronics.
How does it work?
- Power electronic systems demand high blocking voltage in OFF-state and high current in ON-state for efficient switching performance.
- Specific transistors called HEMTs made of aluminium gallium nitride/ gallium nitride (AlGaN/GaN) provides an edge over silicon-based transistors as they allow the systems to operate at very high voltages, switch ON and OFF faster, and occupy less space.
- Commercially available AlGaN/GaN HEMTs use techniques to keep the transistor in a normally OFF state, which affects the stability, performance and reliability of the device.
- Therefore, to meet this need, researchers have developed a new kind of HEMT, which is in the OFF state by default and works like any other commonly used power transistor.