The past few months have seen an intensification of the technological race to miniaturise chips in the belief that mighty products out of little quantum structures do grow. Texas Instruments claimed a first in quantum tunnelling transistors at the end of last year (CI No 1,081) with a breakthrough that meant that a million transistors […]
The past few months have seen an intensification of the technological race to miniaturise chips in the belief that mighty products out of little quantum structures do grow. Texas Instruments claimed a first in quantum tunnelling transistors at the end of last year (CI No 1,081) with a breakthrough that meant that a million transistors would occupy only a square centimetre of Gallium Arsenide and would switch at speeds of around a tenth of a picosecond. This was followed by a report in the January 23 issue of Physical Review Letters that engineers at the University of California, Santa Barbara had successfully constructed and tested a lattice of quantum wires, thereby facilitating the development of quantum electronic structures. The wires – six million of which equal the width of a human hair – were constructed atom by atom from Gallium Arsenide, bounded by an insulation of Aluminium Arsenide, and are hailed as the precursors of a new family of electronic components called quantum structures. These quantum structures are so named because they operate according to the principles of quantum mechanics rather than obeying the everyday laws of physics. For example, in the atomic and subatomic environment, light behaves as particles (or quanta) rather than as waves, while electrons behave as waves rather than as particles. In layman’s terms, this crudely translates into the generalisation that if you make things too small their properties begin to change. In theory this all adds up to an exciting area of innovation for the computer industry, as electrons should travel faster in a quantum wire than in an ordinary wire, suggesting the future manufacture of smaller and more powerful computers. Indeed, there is talk of the possibility of laptop computers that will run on torch batteries but will be as powerful as current supercomputers. The researchers themselves however say it could be 15 years before quantum wires reach the market. Quantum mechanics Hot on the heels of this development, scientists at AT&T Bell Laboratories recently announced that they had created and encapsulated clusters of semiconductor compounds composed of only 100 to 10,000 atoms in a way which stopped the clusters from clumping together, thereby making them easier to work with. A handful of these clusters, which are made of compounds of Zinc, Cadmium, Sulphur, Selenium and other elements, looks and feels like a fine powder. By reducing clusters to the scale of quantum mechanics, John Tully, head of the physical chemistry research department, claims that their strange properties might make them useful someday as switches in computer and communications devices that use light signals instead of electronic signals. This observation was based on the different way the clusters absorb light as their size shrinks. Meanwhile, as all these US developments were coming to light, Nippon Telegraph and Telephone said that it had developed a tiny new transistor that can be used to build smaller, speedier computers and provide clearer pictures on television sets. Another quantum breakthrough, the new quantum wire transistor uses wires one-tenth thickness of current design rules, and can be used to perform calculations at six times the speed possible with existing High Electron Mobility Transistors. The transistor uses wires 5 nanometers thick (one nanometer equals one-millionth of a millimetre) and, aside from placing NTT in direct competition with Texas Instruments in the race for the development of the laptop supercomputer, could also be used to develop more versatile amplifiers for receiving broadcast waves from satellites and other objects in space. This would help provide clearer pictures on television sets. Consequently, it would seem that in the area of quantum structures, the race is not only on to produce the first high powered laptop, but is also spilling over into the research and development contest for the domination of the future high definition TV market.
