Electroluminescence from pure resonant states in hBN-based vertical tunneling junctions  

作　　者：Magdalena Grzeszczyk Kristina Vaklinova Kenji Watanabe Takashi Taniguchi Konstantin SNovoselov Maciej Koperski 

机构地区：[1]Institute for Functional Intelligent Materials,National University of Singapore,Singapore 117544,Singapore [2]Research Center for Functional Materials,National Institute for Materials Science,Tsukuba 305-0044,Japan [3]International Center for Materials Nanoarchitectonics,National Institute for Materials Science,Tsukuba 305-0044,Japan [4]Department of Materials Science and Engineering,National University of Singapore,Singapore 117575,Singapore

出　　处：《Light(Science & Applications)》2024年第8期1557-1564,共8页光（科学与应用)（英文版）

基　　金：supported by the Ministry of Education(Singapore)through the Research Centre of Excellence program(grant EDUN C‐33‐18‐279‐V12,I‐FIM),AcRF Tier 3(MOE2018-T3-1-005);supported by the Ministry of Education,Singapore,under its Academic Research Fund Tier 2(MOE-T2EP50122-0012);supported by the Air Force Office of Scientific Research and the Office of Naval Research Global under award number FA8655-21-1-7026.K.W.;T.T.acknowledge support from JSPS KAKENHI(Grant Numbers 19H05790,20H00354,and 21H05233).

摘　　要：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.

关 键 词：CARBIDE TUNNELING DEFECT 

分 类 号：TP212[自动化与计算机技术—检测技术与自动化装置] O4[自动化与计算机技术—控制科学与工程]