Good job bringing this to light. People won't realise how huge the problem is and municipalities are woefully ill equipped to...
Agreed; mining can never be sustainable, but then how do you get the metals to make all the things you need in the course of...
Very good piece.
a light emitting device developed by researchers at the University of Surrey, uk , may pave the way for a cheaper and more sophisticated optoelectronic devices. Optoelectronics - the combination of electronic and optical functions - is an area which has tremendous applications in communications industry. From compact disks to laser printers and from laser diodes used in fibre optic transmission of gigabytes of information to more mundane applications like traffic signals and display panels, there is hardly an area of modern existence where optoelectronics devices do not find a place ( Nature , Vol 387, No 6634).
Modern electronics is to a large extent based on the semiconducting properties of silicon. This element leads itself to inexpensive fabrication of extremely sophisticated electronic devices which now are ubiquitous.In the last few years, much efforts have gone into the development of silicon integrated optoelectronics devices like silicon-germanium superlattice structures or even erbium doped devices. However, none of these attempts has led to a practical and commercially viable device. The rapid development in this field has been marred by the fact that silicon is a poor emitter of light.
The new device incorporates iron-disilicide, a complex of iron and silicon used to enhance the conductivity of light emitting devices by putting it into a conventional silicon junction. The device operates at a wavelength of 1.5 micrometer, making it ideal for optical fibre communications.
D Leong and his colleagues at Surrey University have incorporated iron-disilicide into a conventional silicon junction diode. After ion implantation at 350 c , the device is subjected to temperatures up to 900 c for 18 hours in a nitrogen atmosphere. The use of an ion beam to make the device is important since ion implantation is almost universal in the production of integrated silicon devices. The led thus obtained was subjected to frequent temperature changes and has performed well for several hours.