The biggest barrier is in the minds of researchers. They are not thinking of new technologies from the manufacturing point of view, and they should. Many basic problems exist for new manufacturing technology. If a new device is invented and the technology to manufacture it does not exist, we cannot use it in the marketplace. For example, single-electron transistors have already been demonstrated, but no one knows how to integrate those devices and access information from them.
Many basic problems have to be solved in order to utilize single-electron transistors.
For example, at NEC we are working on a telephone that can automatically interpret language. So still we have to push. We need huge memory capacity and very high-speed processing power. The development of dynamic RAM chips with 4Gb capacity has been a revolution for the audiovisual industry because it now has the ability to do very complicated things. Researchers are constantly improving processing technology to increase the number of transistors on a chip.