Quantum Dot RAM (QD RAM)
Quantum Dot RAM uses 3nm-wide spots of semiconduictor material, called quantum dots, embedded in a layer of insulating material and covered with a metal film. This structure forms an array of transistors, which are used to store data by changing the state of each quantum dot using a millisecond laser pulse.
This technology is highly promising, as it can achive read/write speeds up to hundres of times faster than existing types of memory, and is also reasonably easy to integrate into existing manufacturing processes, as the chips can still be constructed from silicon. There will be challenges in scaling up the process, but not to the same extent as with implementing a totally new material like carbon nanotubes.
Figure 3. Quantum dots are tiny crystals containing just a few hundred atoms. Memory based on quantum dots could achive much higher storage densities than existing technologies, and would have a vastly longer lifetime.