2023/05/23 by Magdalena Grzeszczyk, Kristina Vaklinova, Grzeszczyk, M. +9 · 1 citation
Engineering · Materials Science · #Diamond and Carbon-based Materials Research #FOS: Physical sciences #Graphene research and applications #Materials Science (cond-mat.mtrl-sci) #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Molecular Junctions and Nanostructures
paper · pdf · doi:10.48550/arxiv.2305.13679
openalex publication_date 2023/05/23 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Defect centers in wide-band-gap crystals attracted considerable attention due to the realisations of qubits, sensors, or single photon emitters at room temperature. The family of these centers is constantly growing, including well-known examples such as nitrogen-vacancy centers in diamond, silicon-vacancy in silicon carbide, chromium substitutions in aluminium oxide, and many others. Unfortunately, such defect centers embedded in highly insulating crystals have been notoriously difficult to excite electrically. Herewith, we present a realisation of insulating light-emitting diodes based on carbon centers in hexagonal boron nitride. The rational design of the vertical tunnelling devices via van der Waals technology enabled us to control the charge dynamics related to non-radiative tunelling, defect-to-band electroluminescence, and intradefect electroluminescence. The fundamental understanding of the tunnelling events enabled us to achieve high efficiency of electrical excitation, which exceeded by a few orders of magnitude the efficiency of optical excitation in the sub-band-gap regime. A combination of a Stark effect and screening by band electrons provide a control knob for tuning the energy of emission. With this work, we solve an outstanding problem of creating electrically driven devices realised with defect centers in wide-band-gap crystals, which are relevant in the domain of optoelectronics, telecommunication, computation, or sensing.