A high-pressure mechanism for realizing sub-10 nm tellurium nanoflakes on arbitrary substrates

Abstract Fundamental studies and technological advancements based on high quality epitaxially grown 2D tellurium are hampered due to strict substrate requirements, which compels to undergo undesirable and time consuming transfer procedures and prevents performing diverse substrate specific studies. Herein, we demonstrate a facile hot-pressing strategy to fabricate high quality sub-10 nm tellurium nanoflakes directly on the substrate of our choice. We further demonstrate that tellurium nanoflakes with thicknesses as low as ~2 nm can be achieved by this strategy. Compared with the peak positions of bulk crystal, peak shifts in Raman spectra for the flakes fabricated on different substrates is an indication of substrate induced strain. The strain-induced band gap variations are probed by the optical studies, which exhibit large photoluminescence from as-prepared tellurium nanoflakes as compared with bulk tellurium. As-prepared nanoflakes further exhibit substrate-dependent structural properties, while maintaining excellent air-stability. We believe that this study will help broadening our understanding towards much less-studied 2D tellurium by facilitating diverse fundamental studies.