Currently, computer chips are made from silicon. It has been this way since the beginning, and the trend of the silicon advances can be modeled by Moore’s law, which says that every few years computer chips will get smaller and more powerful. Specifically, it says that “every three years the amount of data that can be packed onto a chip will increase 4 times.” The Moores law model has been followed since 1960 and has been very accurate. But there is a physical limit to how few silicon atoms can be used for a single transistor gate, about four silicon atoms is the fundamental lower limit for a useable gate. At the rate we are going, we will reach this limit within a few years. At this point we either start making the chips themselves bigger, which is not economically smart, as these chips would require a huge amount of power, and would get extremely hot; both already shortfalls of current chips, or we can look to a new, more efficient way of making out computers. There are several ideas currently being researched:
1. Molecular Technology. These chips will use organic molecules, the same stuff that is used to create our DNA. “Computer simulations have demonstrated that many small molecules exhibit a property known as negative differential resistance. As voltage is increased, the current flowing through molecules drops, meaning they can be used as switches” One would think that with this type of technology there would be no limit to the capacity of processing power and programming techniques, after all, the human brain is basically just a molecular computer. This could be the technology that finally provides the breakthrough to real AI.
http://www.hpl.hp.com/news/molecules_that_compute.html
2. Quantum Chips: “Quantum computers are promising because they can solve certain problems much faster than any possible conventional computer, owing to the bizarre features of quantum mechanics. For instance, quantum computers can process multiple inputs at the same time in the same device.” While current computers use bits, which can hold either a 1 or a 0, quantum computers use qbits, where each qbit can hold the number 1 or 0, or even both 1 and 0 simultaneously. It’s all a bit complicated, but this computer would be able to perform the most complex operations at enormously fast speeds. http://www.physorg.com/news9063.html
3. Optical Quantum Computer: These are very much like traditional Quantum computers as described above, except they use photons rather than electrons, the advantage here is that photons can travel large distances without losing their quantum properties, and they do not get hot like electrons do. Also they would theoretically use much less energy than any electron model. http://physicsworld.com/cws/article/news/40306
I’m sure there are other potential models out there that I have not identified, but regardless of which technology will be replacing silicon, the fact is that something will be. The transition from silicon to another type of computer chip could prove to be troublesome in several ways. First of all, the switch would in no way be unanimous; millions of people do not have the money to upgrade their system and will no doubt stay with the current silicon chip technology for years. This means that any new technology will have to be backwards compatible with a silicon based computer. The same would go for most software developed after the switch. That brings me to the next barrier: programming. Now I can’t be sure, but I would assume that new programming languages and techniques would have to be used for a different technology.
One thing is for sure, it will be the biggest switch our society will have to undergo since the computer itself came along, but now as then, it is be sure to be a slow and gradual switch.