In the world of electronics, transistors are the key components that power our devices, from smartphones to computers.
As these devices get smaller and more powerful, the transistors inside them need to keep up. However, traditional transistors are facing challenges as they shrink in size.
To overcome these hurdles, scientists are exploring new ways to improve transistor performance, and a recent breakthrough has opened up exciting possibilities.
A team of researchers from the Institute of Metal Research (IMR) at the Chinese Academy of Sciences, led by Professors Liu Chi, Sun Dongming, and Cheng Huiming, has developed a new type of transistor that could revolutionize future electronics.
This new transistor is called a “hot-emitter transistor” (HOET) and is based on a novel mechanism known as stimulated emission of heated carriers (SEHC). This innovation could lead to faster, more energy-efficient devices.
Hot carrier transistors, like the one developed by this team, work by using the extra kinetic energy of carriers—tiny particles that carry electrical charge through the transistor.
This energy can help the transistor operate faster and perform more functions. However, until now, the performance of hot carrier transistors has been limited by the methods used to generate these hot carriers.
The team at IMR has changed that by introducing the SEHC mechanism, which allows for more efficient generation of hot carriers. To create their hot-emitter transistor, the researchers used a combination of graphene and germanium—two materials known for their excellent electrical properties.
Graphene, in particular, is only one atom thick and has no surface defects, making it an ideal material for forming strong connections with other materials.
The new transistor is made up of two connected graphene/germanium junctions, which work together to generate hot carriers more effectively. When the transistor is in operation, germanium injects high-energy carriers into the graphene base.
These carriers then move to the emitter, leading to a significant increase in current due to the preheated carriers.
One of the most remarkable achievements of this new transistor is its extremely low sub-threshold swing—less than 1 millivolt per decade (mV/dec).
This is a measure of how efficiently the transistor can switch on and off, and a lower value indicates better performance. The HOET’s sub-threshold swing is much lower than the conventional limit of 60 mV/dec, meaning it can operate with much less power.
Additionally, this transistor has a peak-to-valley current ratio of over 100, even at room temperature. This feature makes it possible to perform multi-valued logic computing, a technique that could further enhance the capabilities of future electronic devices.
“This research opens up a new area in transistor technology, adding a valuable member to the family of hot carrier transistors,” said Professor Liu. “It shows great promise for future high-performance, low-power, multifunctional devices.”
This breakthrough could lead to the development of faster, more efficient electronics, making our devices even more powerful while consuming less energy.
As we move into the post-Moore era, where traditional transistor technology reaches its limits, innovations like the hot-emitter transistor will be key to driving the next generation of technology.
