Research data for: Electroluminescence from pure resonant states in hBN-based vertical tunneling junctions

The experimental data is related to the article: Electroluminescence from Pure Resonant States in hBN-based Vertical Tunneling Junctions.Defect centers in wide-band-gap crystals have garnered interest for their potential in applications among optoelectronic and sensor technologies. However, defects embedded in highly insulating crystals, like diamond, silicon carbide, or aluminum oxide, have been notoriously difficult to excite electrically due to their large internal resistance. To address this challenge, we realized a new paradigm of exciting defects in vertical tunneling junctions based on carbon centers in hexagonal boron nitride (hBN). The rational design of the devices via van der Waals technology enabled us to raise and control optical processes related to defect-to-band and intradefect electroluminescence. The fundamental understanding of the tunneling events was based on the transfer of the electronic wave function amplitude between resonant defect states in hBN to the metallic state in graphene, which leads to dramatic changes in the characteristics of electrons due to different band structures of constituent materials. In our devices, the decay of electrons via tunneling pathways competed with radiative recombination, resulting in an unprecedented degree of tuneability of carrier dynamics due to the significant sensitivity of the characteristic tunneling times on the thickness and structure of the barrier. This enabled us to achieve a high-efficiency electrical excitation of intradefect transitions, exceeding by several orders of magnitude the efficiency of optical excitation in the sub-band-gap regime. This work represents a significant advancement towards a universal and scalable platform for electrically driven devices utilizing defect centers in wide-band-gap crystals with properties modulated via activation of different tunneling mechanisms at a level of device engineering.

本实验数据关联于题为《六方氮化硼（hexagonal boron nitride, hBN）基垂直隧穿结中纯共振态的电致发光》的研究论文。宽带隙晶体中的缺陷中心因其在光电子与传感技术领域的应用潜力而广受关注。然而，嵌入金刚石、碳化硅或氧化铝等高绝缘晶体中的缺陷，因其内部电阻率极高，历来难以实现电激发。为应对这一挑战，我们基于六方氮化硼中的碳缺陷中心，在垂直隧穿结中实现了缺陷电激发的全新范式。通过范德华（van der Waals）技术对器件进行合理设计，我们得以优化并调控与缺陷-能带跃迁及缺陷内部电致发光相关的光学过程。我们对隧穿过程的基础理解基于电子波函数振幅从六方氮化硼的共振缺陷态向石墨烯（graphene）的金属态的转移，这一转移会因组成材料的能带结构差异引发电子特性的显著变化。在我们的器件中，电子通过隧穿路径的弛豫过程与辐射复合过程相互竞争，而特征隧穿时间对势垒厚度与结构具有极强的敏感性，这使得载流子动力学具备了前所未有的高可调谐性。这使得我们能够实现缺陷内部跃迁的高效电激发，其效率较亚带隙区域的光激发效率高出数个数量级。本研究朝着构建通用且可规模化的电驱动器件平台迈出了重要一步，这类器件借助宽带隙晶体中的缺陷中心实现工作，其性能可通过器件工程层面激活不同隧穿机制来调控。