Semi Im
Pohang University of Science and Technology – Pohang, Republic of Korea
_______________________________________
Hexagonal boron nitride (h-BN) has emerged as a promising host material for optically active defects, exhibiting stable single-photon emission at room-temperature, high quantum efficiency, and exceptional photostability under extreme conditions. In particular, carbon-related defects in h-BN have recently attracted substantial interest due to the high brightness and stable operation in wide range of emission wavelengths, from ultraviolet (UV) to near-infrared (NIR). Here, we synthesized carbon-incorporated h-BN using metal-organic chemical vapor deposition (MOCVD) and achieved the electroluminescence from wafer-scale h-BN films for the first time. The chemical states of incorporated carbon atoms are studied by multiple spectroscopic techniques, including Raman spectroscopy, UV-Vis spectroscopy, and near-edge X-ray absorption fine structure (NEXAFS). Crystallographic analysis via synchrotron radiation X-ray diffraction (XRD) further confirmed the distinct six-fold symmetry of h-BN and demonstrated that the crystallinity was maintained after carbon incorporation. We investigated the optimal thickness of h-BN as an emissive layer, taking advantage of the precise thickness controllability by MOCVD over a broad range of 2 to 50 nm. We then fabricated simple light emitting devices using a carbon-incorporated h-BN as an emissive layer, and we demonstrated intense electroluminescence (EL) in band-edge DUV region as well as NUV region. An optical phonon-assisted emission derived from indirect bandgap transition was observed at the band-edge region, and the quantum emission with distinct zero phonon line (ZPL) and phonon side bands (PSBs) are well matched with what originating from C2 dimers or C6 rings formed by the incorporated carbon atoms in h-BN lattice. The intense and discrete band-edge and NUV EL spectra evidence high crystallinity of carbon-incorporated h-BN, and feasibility of atomic-level precise control of carbon incorporation. Unlike previous studies, where h-BN was primarily utilized as a passive component in conventional semiconductor technology, our findings demonstrate its potential as a crucial component for optoelectronic applications by fully leveraging its exceptional optical properties. The large-scale synthesis of carbon-incorporated h-BN via MOCVD with controllable defect densities and its electroluminescence represents a significant step toward the realization of on-chip distributed quantum photonic devices.
Email: kimjk@postech.ac.kr