Quantum Dots - Will it succeed the Semiconductor Transistor?

Currently, in electronics, one hot topic steadily gathering engineers' interest worldwide is Quantum Dots (or QDs in short).

So, what exactly do you mean by Quantum Dots?

Quantum Dots refer to semiconductor particles only a few nanometers in size. Due to their small size, these particles fall under the domain of quantum mechanics and are subject to the properties of the Quantum Realm. This makes quantum dots have properties different from bulk semiconductors and closer to individual atoms/molecules. These properties can be used to create new amazing devices, which can bring about a lot of new possibilities. (Who knows, it may help make that cool Iron Man suit from Avengers: Infinity War!)

Quantum dots and Nanotechnology:

Quantum dots are considered to be the building blocks of nanotechnology. They are based on the property that electron transition can either release or consume energy in the form of light. Quantum dots have optical and electrical properties that depend on the particles’ size, shape, and composition. Large QDs (5–6 nm diameter) emit longer wavelengths, with colors like orange, red or yellow. Smaller QDs (2–3 nm diameter) emit shorter wavelengths, giving colors like blue, green, and violet.

Many researchers around the globe are trying to make use of Quantum dots to make conventional electronic devices such as single-electron transistors, solar cells, LEDs, and lasers. One major application of Quantum dots in consumer electronics came from Samsung in 2017 with its introduction of the Quantum Dot LED TV (or QLED TV) range. These are LCD-based TVs augmented with quantum dot nanocrystals. They provided a viewing resolution of 4K and 8K and were highly praised for their viewing quality.

Other than electronics, Quantum Dots has shown numerous applications in biology. They are used in modern biological analysis to detect different molecules in the body. Quantum dots can also be used for antibacterial purposes. Single-molecule tracking experiments are possible as well because of current developments in the field.

However, one application of Quantum Dots that can have immense potential is the Quantum Field Effect Transistor (QFET).

The Quantum Field Effect Transistor (QFET)

For many years, transistors have been used in everyday life for a lot more purposes than we can imagine. In modern-day computers, ranging from supercomputers to even your newly-bought smartphone, transistors are everywhere. Currently, an average computer circuit consists of more than a billion transistors, and it’s still growing. However, here’s the catch: as the number of transistors increase, the size of the transistors decreases at the same rate. The size of a transistor is currently at 7 nm (about 7/1,000,000th of a millimeter.)

Moore’s Law states that the number of transistors in a dense integrated circuit (IC) doubles every two years. However, since the year 2010, the observations in the industry have been slightly less than the predicted value. This is because as of now, we are reaching a physical limit for downsizing transistors and Moore’s Law may be invalid in the next few decades.

In a situation like this, Quantum dots may have great potential for faster devices because using this, it might be possible to achieve even smaller transistors. Currently, numerous efforts are being made to design field effect transistors (FETs) using Quantum Dots, which can additionally increase the speed of the charge carriers (like electrons and holes) by a factor of 3000.

So, what next??

Quantum dots is still a developing field, with many facts about the subject still being unknown or uncertain. But new applications and discoveries in the field are coming up every day, with each being more fascinating than before. As this topic continues to create ripples in the world of science, many believe that Quantum Dots can pave the way for the future of electronics.

-Sreevatsa Murthy