On December 23, a research group from the Department of Advanced Materials Engineering of Pohang University of Technology announced that they have produced a new type of LED element that can emit deep ultraviolet light based on a sandwich structure of graphene and hexagonal boron nitride (hBN) layers. . The research team explained that so far, devices that emit deep ultraviolet rays mainly use components made of mercury or aluminum gallium nitride, but these traditional components have problems with pollution or luminous efficiency. The research results were recently published in the world-renowned academic journal "Nature Communications".
▲ h-BN deep ultraviolet LED. The schematic diagram shows that the use of graphene, h-BN and van der Waals heterogeneous nanomaterials with graphene structure can emit strong deep ultraviolet light (C)
Segons la Universitat Tecnològica de Pohang, el principal material que s'utilitza actualment en la investigació del LED ultraviolat-profund és el nitrur de gal·li d'alumini (d'ara endavant anomenat AlxGa1-xN). Tanmateix, aquest material té una limitació bàsica, és a dir, a mesura que la longitud d'ona es fa més curta, les característiques d'emissió de llum es deterioraran ràpidament.
In order to break through this limitation, Pohang University of Technology uses h-BN as a device material. The structure of its single atomic layer is similar to graphene, and its appearance is transparent, so it is also called "white graphene."
S'informa que, a diferència d'AlxGa1-xN, emet llum brillant a la regió ultraviolada profunda i es considera un material nou que es pot utilitzar per desenvolupar LED ultraviolats profunds. Tanmateix, a causa de la gran bretxa de banda, és difícil injectar electrons i forats, cosa que fa impossible fer un LED. Tanmateix, si s'aplica una tensió forta a la pel·lícula h-BN nano-, es poden injectar electrons i forats mitjançant l'efecte de túnel. Per tant, es van fabricar dispositius LED basats en nanomaterials heterogenis de Van der Waals apilats amb grafè, h-BN i grafè, i l'espectroscòpia ultraviolada profunda va confirmar que els dispositius reals emeten forts raigs ultraviolats.
Professor Jin Zhonghuan from the Department of Materials Science and Engineering of the university said: "The development of new high-efficiency LED materials in the new wavelength range can be a starting point for the application of optical devices. The significance of this research on h-BN lies in the realization of deep-ultraviolet LED manufacturing. .
In addition, compared with the existing AlxGa1-xN material, it has significantly higher luminous efficiency, and the device can be miniaturized. "
