A novel lighting device using carbon nanotubes that could give competition to conventional light bulbs and fluorescent bulbs has been developed by researchers at Ecole Polytechnique in Lausanne, France. The device uses a central wire covered with carbon nanotubes that gives out electrons when a voltage is applied. These electrons strike the outer glass envelope, which is coated with a phosphor. The coating absorbs the electrons and emits light. The advantage of the new light source is that it can be dimmed and switched on instantly. The light source is only 10 per cent efficient as of now, but researchers feel that this could be improved ( Applied Physics Letters , April 30, 2001).