Effective Passivation of Exfoliated Black Phosphorus Transistors against Ambient Degradation
Year: 2014
Type: article
Abstract: Unencapsulated, exfoliated black phosphorus (BP) flakes are found to chemically degrade upon exposure to ambient conditions. Atomic force microscopy, electrostatic force microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy are employed to characterize the structure and chemistry of the degradation process, suggesting that O2 saturated H2O irreversibly reacts with BP to form oxidized phosphorus species. This interpretation is further supported by the observation that BP degradation occurs more rapidly on hydrophobic octadecyltrichlorosilane self-assembled monolayers and on H-Si(111) versus hydrophilic SiO2. For unencapsulated BP field-effect transistors, the ambient degradation causes large increases in threshold voltage after 6 h in ambient, followed by a ∼ 10(3) decrease in FET current on/off ratio and mobility after 48 h. Atomic layer deposited AlOx overlayers effectively suppress ambient degradation, allowing encapsulated BP FETs to maintain high on/off ratios of ∼ 10(3) and mobilities of ∼ 100 cm(2) V(-1) s(-1) for over 2 weeks in ambient conditions. This work shows that the ambient degradation of BP can be managed effectively when the flakes are sufficiently passivated. In turn, our strategy for enhancing BP environmental stability will accelerate efforts to implement BP in electronic and optoelectronic applications.
Source: Nano Letters
DOI: 10.1021/nl5032293
Authors: Joshua D. Wood, Spencer A. Wells, Deep Jariwala, Kan-Sheng Chen, EunKyung Cho, Vinod K. Sangwan, Xiaolong Liu, Lincoln J. Lauhon, Tobin J. Marks, Mark C. Hersam
Institution: Northwestern University
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
Funders: National Science Foundation, U.S. Department of Defense, U.S. Department of Energy, W. M. Keck Foundation, Northwestern University, Office of Science, Materials Research Science and Engineering Center, Harvard University, National Defense Science and Engineering Graduate, Office of Naval Research, Division of Materials Research, Basic Energy Sciences, Argonne National Laboratory
Awards: G102163711, G107546177, G1286251239, G1313983767, G1657001476, G1664757510, G2287611682, G2379832748, G262962599, G3075337988, G318734614, G426311843, G498139845, G5387317844, G5472666041, G5633509676, G6918803902, G7178204, G7583137537, CEMRI: Multifunctional Nanoscale Material Structures, Nanoscale Science & Engineering Center for Integrated Nanopatterning and Detection Technologies, G914357938, G993149817
OpenAlex ID: W1980874018