Phys.org October 22, 2024
Single-crystal hexagonal boron nitride (hBN) is used extensively in many two-dimensional electronic and quantum devices, where defects significantly impact performance. An international team of researchers (Norway, Germany) examined the capture and emission dynamics of defects in hBN by utilizing low-frequency noise (LFN) spectroscopy in hBN-encapsulated and graphene-contacted MoS2 field-effect transistors (FETs). The low disorder of this heterostructure allowed the detection of random telegraph signals (RTS) in large device dimensions of 100 μm2 at cryogenic temperatures. Analysis of gate bias- and temperature-dependent LFN data indicated that RTS originated from a single trap species within hBN. Through calculations on a gated defective hBN/MoS2 heterostructure model, they assigned substitutional carbon atoms in boron sites as the atomistic origin of RTS. According to the researchers, their study demonstrated that the utility of LFN spectroscopy combined with MS-DFT analysis on a low-disorder all-vdW FET as a powerful means for characterizing the atomistic defects in single-crystal hBN… read more. Open Access TECHNICAL ARTICLE
Graphical abstract. Credit: ACS Nano, Vol 18, Issue 42, 28 September 2024