Giant Thermomechanical Bandgap Modulation in Quasi-2D Tellurium

Hussain N., Ahmed S., Tepe H. U., Ullah K., SHEHZAD K., Wu H., ...Daha Fazla

Advanced Functional Materials, cilt.34, sa.46, 2024 (SCI-Expanded) identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 34 Sayı: 46
  • Basım Tarihi: 2024
  • Doi Numarası: 10.1002/adfm.202407812
  • Dergi Adı: Advanced Functional Materials
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Applied Science & Technology Source, Chemical Abstracts Core, Chimica, Communication Abstracts, Compendex, INSPEC, MEDLINE, Metadex, Civil Engineering Abstracts
  • Anahtar Kelimeler: bandgap, engineering, hot pressing, non-volatile strain, optoelectronics, tellurium
  • Orta Doğu Teknik Üniversitesi Adresli: Evet

Özet

Lattice deformation via substrate-driven mechanical straining of 2D materials can profoundly modulate their bandgap by altering the electronic band structure. However, such bandgap modulation is typically short-lived and weak due to substrate slippage, which restores lattice symmetry and limits strain transfer. Here, it is shown that a non-volatile thermomechanical strain induced during hot-press synthesis results in giant modulation of the inherent bandgap in quasi-2D tellurium nanoflakes (TeNFs). By leveraging the thermal expansion coefficient (TEC) mismatch and maintaining a pressure-enforced non-slip condition between TeNFs and the substrate, a non-volatile and anisotropic compressive strain is attained with ε = −4.01% along zigzag lattice orientation and average biaxial strain of −3.46%. This results in a massive permanent bandgap modulation of 2.3 eV at a rate S (ΔEg) of up to 815 meV/% (TeNF/ITO), exceeding the highest reported values by 200%. Furthermore, TeNFs display long-term strain retention and exhibit robust band-to-band blue photoemission featuring an intrinsic quantum efficiency of 80%. The results show that non-volatile thermomechanical straining is an efficient substrate-based bandgap modulation technique scalable to other 2D semiconductors and van der Waals materials for on-demand nano-optoelectronic properties.