AFM and Raman studies of topological insulator materials subject to argon plasma etching

Abstract

Plasma etching is an important tool in nano-device fabrication. We report a study on argon plasma etching of topological insulator materials Bi2Se3, Bi2Te3, Sb2Te3 and Bi2Te2Se using exfoliated flakes (with starting thicknesses of ~100 nm) derived from bulk crystals. We present data mainly from atomic force microscopy (AFM) and Raman spectroscopy. Through AFM measurements, plasma exposure is observed to decrease the thickness of our samples and increase surface roughness (with height fluctuations reaching as large as ~20 nm). We extract an etching rate for each type of material. Plasma exposure also causes a widening (especially Eg2) of the characteristic Raman peaks, with no significant change in peak position. The overall Raman intensity is observed to initially increase, then decrease sharply after the samples are etched below ~20 nm in thickness. Our findings are valuable for understanding the effects of argon plasma etching on topological insulator materials.

arXiv comment12 pages, 9 figures

References in corpus (10)

• First observation of Spin-Momentum Helical Locking in Bi2Se3 and Bi2Te3, demonstration of Topological-Order at 300K and a realization of topological-transport-regime
• Three-Dimensional Topological Insulators
• Gate-Voltage Control of Chemical Potential and Weak Anti-localization in Bismuth Selenide
• Interference enhancement of Raman signal of graphene
• Micro-Raman Spectroscopy of Mechanically Exfoliated Few-Quintuple Layers of Bi(2)Te(3), Bi(2)Se(3) and Sb(2)Te(3) Materials
• Interference effect on Raman spectrum of graphene on SiO_2/Si
• Effect of oxygen plasma etching on graphene studied with Raman spectroscopy and electronic transport
• Crystal Symmetry Breaking in Few-Quintuple Bismuth Telluride Films: Applications in Nanometrology of Topological Insulators
• Fabrication and Characterization of Topological Insulator Bi${}_2$Se${}_3$ Nanocrystals
• Stability of exfoliated Bi${}_2$Sr${}_2$Dy${}_x$Ca${}_{1-x}$Cu${}_2$O${}_{8+\delta }$ studied by Raman microscopy

Cited by in corpus (6)

• Aharonov-Bohm Oscillations in a Quasi-Ballistic 3D Topological Insulator Nanowire
• Thickness tunable quantum interference between surface phonon and Dirac plasmon states in thin-films of the topological insulator Bi2Se3
• Plasmon-enhanced electron-phonon coupling in Dirac surface states of the thin-film topological insulator Bi2Se3
• Materials analysis and focused ion beam nanofabrication of topological insulator Bi2Se3
• Low vibration high numerical aperture automated variable temperature Raman microscope
• Topological Phase Transition-Induced Tri-Axial Vector Magnetoresistance in (Bi1-xInx)2Se3 Nanodevices