In our contemporary state of affairs, it is fairly safe to say that incandescent lamps are being commercially replaced by more efficient CFL and LED lighting solutions. However, Professor Yue Kuo, from the Texas A&M University, and his former Ph.D. student Chi-Chou Lin, have literally gone back to ‘basics’ – with their contrivance of a solid-state device. This bantam gizmo works on the same principle as that of a conventional incandescent lamp, but the filaments used here are far more tiny, with sizes ranging from 20 to 150 nanometers (in diameter). The end result pertains to the wondrous achievement of incandescence at a microscopic level.

According to the researchers involved in the project, their creation pertains to a solid-state version of the famed incandescent lamp originally commercialized by Thomas Edison. As a matter of fact, Prof. Kuo has named the light bulb as ‘solid-state incandescent LED’ – where the D stands for device, instead of diode. This entire microscopic contraption comprises of a layer of dielectric material (which is amorphous, and has insulating property) that is kept between a conductor and p-type silicon. The illumination we see in the image is comprehensible due to the transparent, conducting film (presumably indium tin oxide) atop the conductor.

So, how does the light emission take place? Well, a current with a high enough voltage, passed through the aforementioned dielectric layer, allows its disintegration into a slew of tiny yet conductive filaments. The sustenance of the voltage ‘fuels’ current flow through these filaments, and in turn is offered electrical resistance – thus ultimately resulting in dots of heated lights. The dielectric layer in question can be composed from relatively-common transistor compounds like tungsten oxide and halfnium oxide.

In fact, the easy availability of the required materials, complemented by the simple manufacturing process (that can be done by regular semiconductor-making plants), comes out as a significant advantage for the solid-state incandescent LED. But all of these benefits will have little value if the resultant microscopic light bulb doesn’t account for efficiency. To that end, the researchers are looking forth to more effective conversion of electricity into light. This might just be easier for the solid-state device since it peaks in the visible end of the spectrum, as opposed to conventional incandescent lights that peak in the infrared zone.

Lastly, the question arises – will the solid-state incandescent LED be feasible enough to work as an alternative to light emitting diodes (LEDs)? Well, according to Prof. Kuo, the development of the microscopic device is in a nascent stage, with far too variables relating to its conductivity and limitations. So, the answer to the query is not so simple, at least in the present phase of development process. However, Professor Michael Shur, from the Rensselaer Polytechnic Institute in Troy, has made his support known for the technology, by saying –

I think it’s a very interesting, I would even say, a brilliant idea. Potentially it could be very cheap, it could be very robust, and it could cover a huge area. This is the technology of the future, in my opinion.

Source: SpectrumIEEE