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.

12 pages, 9 figures

References in corpus (5)

• Gate-Voltage Control of Chemical Potential and Weak Anti-localization in Bismuth Selenide
• Interference enhancement of Raman signal of graphene
• 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
• 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 (2)

• Thickness tunable quantum interference between surface phonon and Dirac plasmon states in thin-films of the topological insulator Bi2Se3
• Materials analysis and focused ion beam nanofabrication of topological insulator Bi2Se3