Only three atoms thick LED, the future is expected to open a transparent display

In 2015, the University of California at Berkeley (UC Berkeley) Ali Javey professor of electrical engineering and computer science, in scientific journals (Science) published an article that revealed by single semiconductor (monolayer semiconductor) made the possibility of ultra-thin LEDs. But the technology at the time, if the size of the semiconductor layer to expand, thickness will also increase, the real application of co..

The day before, the team has successfully made to extend the length and width at the same time without affecting the thickness, and only three atoms thick LEDs. The new research results have been published in "nature" Journal of communication (Nature Communications).

LEDs

When a voltage is applied to the LEDs, will reach the electronic excited state (excited state), and then when it is at the point of contact hole and meet, will decay to the ground state (ground state), while the energy released in the form of light. This is the LEDs mode of operation. Therefore, the difficult problem is to improve the LEDs luminous efficiency problems, how to make the free electron and hole more efficient contact. Especially when only single thick size semiconductor, which can use the material is not much, the more difficult to improve.

Single semiconductor

But researchers in two transition metal chalcogenides (Transition-metal dichalcogenides, referred to as TMDCs) made of semiconductor material with semiconductor monolayer, this characteristic is similar to that of graphene, is considered to be an important photoelectric material for the next generation. Then in the semiconductor placed under the gate (Gate) and the source (Source) made of LEDs, when the AC in the gate and the source are inter connected, free electrons and holes will also appear in the middle of the semiconductor layer, and the light energy to release.

The configuration of LEDs ^. (photo: Ali Javey)

The future development

At present this LEDs there are still many places need continuous improvement, especially its energy efficiency is only 1%, far less than the commercially available 25 ~ 30%. But as the research team postdoctoral researcher Der-Hsien Lien said: "this material is thin and flexible, so it can be made transparent and applied to curved surface". The transparent display has become the new target of science and technology, have a considerable impact on the results of this study will be.

In addition, through chemical vapor deposition (chemical vapor deposition studies have made a large number of high quality TMDCs), it is expected to borrow from the characteristics of solving physical problems currently facing the limit of integrated circuit.

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