BY Kit Eaton
While there’s a lot of work to push nanotechnology as the future of computer chips, good old-fashioned semiconductors still have a lot of life in them yet: and they’ve recently been given a boost with a radical new type of circuit element that incorporates both semiconductor and nanotechnology.
Its called the memristor, and if you haven’t heard of it that’s not much of surprise–they were only manufactured for the first time last year. Memristors are tiny electronic devices that change their electrical resistance proportionally to the current running through them–in contrast transistors “turn on” current when a small input voltage is applied. Unlike transistors, memristors don’t forget their state when they’re turned off, making them useful as non-volatile memory for example.
Now a team from Hewlett-Packard labs in Palo-Alto has demonstrated a hybrid transistor-memristor circuit for the first time, using a nanowire grid and titanium dioxide as a semiconductor. The resulting device had memristors at the nanowire junctions and was surrounded by transistors.
Why should you get excited about this? For one reason–a transistor/memristor paired assembly can be programmed to either behave like a traditional logic circuit, route signals across it or behave as a memory storage unit. And these are all tasks that require specially-engineered circuitry in existing chips. In other words, a memristor-chip could pack in much more processing power in the same area–and that’s the trend that our increasingly-powerful chips have been following for decades.
Yet more interestingly, since the memristor “remembers” what state its in, by doing a calculation with a group of the circuits and feeding back the output of a calculation to the same memristors, the device could effectively “self-program.” As HP spokesman Tim Williams puts it: “self-programming is a form of learning. Thus, circuits with memristors may have the capacity to learn how to perform a task, rather than have to be programmed to do it.”
And that’s one long-predicted goal of computing technology that may even enable synaptic-like responses. Your computer in ten years time may do some of your thinking for you.