Characterizing Defects Inside Hexagonal Boron Nitride Using Random Telegraph Signals in van der Waals 2D Transistors.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 39340839.
- Also identified by DOI 10.1021/acsnano.4c06929 and PMC identifier 11503768.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Single-crystal hexagonal boron nitride (hBN) is used extensively in many two-dimensional electronic and quantum devices, where defects significantly impact performance. Therefore, characterizing and engineering hBN defects are crucial for advancing these technologies. Here, we examine the capture and emission dynamics of defects in hBN by utilizing low-frequency noise (LFN) spectroscopy in hBN-encapsulated and graphene-contacted MoS<sub>2</sub> field-effect transistors (FETs). The low disorder of this heterostructure allows the detection of random telegraph signals (RTS) in large device dimensions of 100 μm<sup>2</sup> at cryogenic temperatures. Analysis of gate bias- and temperature-dependent LFN data indicates that RTS originates from a single trap species within hBN. By performing multispace density functional theory (MS-DFT) calculations on a gated defective hBN/MoS<sub>2</sub> heterostructure model, we assign substitutional carbon atoms in boron sites as the atomistic origin of RTS. This study demonstrates 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.