Electron-hole asymmetry in the electron-phonon coupling in top-gated phosphorene transistor

• Published in: 2d materials Vol. 3; no. 1; p. 15008
• Main Authors: Chakraborty, Biswanath, Gupta, Satyendra Nath, Singh, Anjali, Kuiri, Manabendra, Kumar, Chandan, Muthu, D V S, Das, Anindya, Waghmare, U V, Sood, A K
• Format: Journal Article
• Language: English
• Published: IOP Publishing 18.02.2016
• Subjects: Asymmetry; Channels; Conduction band; Constitution; Coupling; electron-phonon coupling; phonon; Phonons; phosphorene; Raman spectroscopy; Semiconductor devices; Symmetry
• ISSN: 2053-1583; 2053-1583
• DOI: 10.1088/2053-1583/3/1/015008

Using in situ Raman scattering from phosphorene channel in an electrochemically top-gated field effect transistor, we show that phonons with Ag symmetry depend much more strongly on concentration of electrons than that of holes, wheras phonons with Bg symmetry are insensitive to doping. With first-principles theoretical analysis, we show that the observed electon-hole asymmetry arises from the radically different constitution of its conduction and valence bands involving π and bonding states respectively, whose symmetry permits coupling with only the phonons that preserve the lattice symmetry. Thus, Raman spectroscopy is a non-invasive tool for measuring electron concentration in phosphorene-based nanoelectronic devices.