Free Radicals - Michael Brooks [94]
The materials that interested Ovshinsky are properly called ‘amorphous’: without defined shape or structure. The glass in your window is amorphous: the silicon dioxide molecules in the panes that let light into your house are arranged in no particular way. If you were to look at them under an electron microscope, you would see a jumble of molecules: there is no order beyond the tetrahedral arrangement of the silicon and oxygen atoms that make up each molecule. The idea that amorphous materials might prove useful was bolstered by Ovshinsky’s new interest. His reading had led him to a fascination with the brain. If the messy, disordered structure of brain cells produced the powerful organic computer inside our skulls, he reasoned, then perhaps materials without an ordered structure could also have electrical properties as interesting as those being found by researchers in the silicon industry.
Ovshinsky knew that the transistor works by controlling a crystal’s conductivity. If you apply energy in the form of an electric field, you can switch the crystal from blocking the flow of electric current to conducting it. Perhaps, he thought, energy – whether light, electricity or even heat – could do similar things to an amorphous solid. Perhaps it would jolt the atoms into a more useful arrangement, and give the solid some interesting properties. Perhaps it would even be reversible. His early experience with the development of the lathe had taught Ovshinsky that crazy ideas need more than an enthusiastic advocate: they need a prototype. And so he set about trying to create his own amorphous version of the transistor.
Eventually, it worked. Ovshinsky’s threshold switch was a thin film of amorphous material sandwiched between two metal conductors. When a large enough voltage was applied across these conductors, the amorphous material would become a crystal. That changed it from being an insulator to being a conductor, just like that. When the voltage was reduced, it would switch back.
As if that wasn’t revolutionary enough, Ovshinsky created another material in which the switch between conducting and insulating states didn’t need a continuous flow of electrical power. You hit the material with a burst of electricity, and it went from one state to the other and would stay in whatever state you left it until you applied another voltage. The technology is a kind of non-volatile memory, the kind used in the memory sticks that you plug into your USB drive to transfer stored data. Ovshinsky’s patent has now been licensed by the chip-maker Intel, among others. In the United States of the 1960s, however, no one who mattered put any credence in Ovshinsky’s claims. Getting amorphous materials to switch between conducting and insulating states was thought to be impossible, so no one believed Ovshinsky when he said he had got it to work.
A February 1970 article in the magazine Science & Mechanics illustrates the reaction of the scientific establishment. It was called ‘The Ovshinsky Invention’, and examined his claim that if you applied a voltage to a particular type of glass, it would conduct electricity. If this was true, it was a discovery that would threaten the newly established dominance of the silicon transistor. The article’s subtitle made clear the mood of the time: ‘Is it greater than the transistor, or is this self-taught engineer a fraud as the big companies claim?’
It was this kind of hostility and scepticism that sent Ovshinsky, who was now close to bankruptcy, to Japan. His early inventions were licensed by Canon, Sony, Sharp and Matsushita – companies that became the superpowers of the Japanese electronics industry. Thanks to Japanese investment, Ovshinsky’s inventions now occupy a key place in the technological landscape. The flat LCD display in your TV and your computer monitor, a screen that really can be ‘hung on the wall