From Silicon Valley to the Rust Belt - the Rise of Nanotechnology

by Typher Yom '19

The silicon age: it represents the triumph of today in the field of electronics, and the advancement of human innovation. Will this age ever end? Moore’s law seems to say so. According to this law, the size of our transistors, which are made of silicon, will get two times smaller approximately every two years. But silicon chips can only be so small: after a certain size, we can’t make functioning transistors and further improve our electronics.

Silicon is the pinnacle of today’s electronics; from silicon chips in computers to silicon transistors in our radios, there are hardly any types of electronics that do not use silicon. Its semiconducting properties allow it to switch on and off at room temperature. Without this “switch” ability, our computer chips, would not be able to hold the abundance of memory and information at our fingertips. Silicon is not the ideal electronic material, but this disadvantage is balanced by its abundance, as silicon is the 8th most abundant element on Earth. Other semiconductors, like gallium arsenide, are much less accessible, especially now, since we are so dependent on the use of electronics that semiconductors are in high demand.

Silicon is the 8th most abundant element on Earth, just after nitrogen.

So if we hit the limit on silicon, will progress in electronics stop? Will we ever be able to create better and smaller computers?
Our answer lies not with silicon, but with nanotechnology. One of the more  promising replacements for silicon is 2-dimensional materials. The discovery of graphene – a sheet of carbon atoms put together in a honeycomb structure – in 2004 sparked a race to find more 2-D materials, each with its own unique properties. Since graphene, we have found materials such as molybdenum disulfide and boron nitride, each with its own unique properties and its own potential as a successor to silicon. Recently, perovskite hybrid sheets, a new kind of 2-D material,  have been produced in the Berkeley National Laboratory. But unlike all of the other two dimensional materials we have discovered, the atoms of this material are connected via ionic bonds instead of covalent bonds, giving perovskite hybrid sheets fundamentally different optical and electrical properties.

Conventional 3-D perovskites have fascinating electromagnetic properties, such as piezoelectricity (electricity created from mechanical stress) and superconductivity (the ability to conduct electrons without having them lose energy). Letian Dou was able to devise a production method that would result in the two dimensional, rather than the three dimensional form, of perovskite.
 
The geometry of these 2-D square crystals is very well-defined, and the crystals are quite large, allowing them to be easily integrated into future electronic devices. Yang states that they “open up new possibilities for the design of materials/devices on a n atomic/molecular scale with distinctive new properties.”

In Michio Kaku's words, "we're going to leave the Silicon Age soon and enter the Nano Age.  Silicon Valley will become a Rust Belt, unless they can find a replacement for silicon." The end of the silicon age will herald newer, brighter, and more powerful computers in the future.