Substituent-induced modulation of quantum transport in semiconducting 7-armchair graphene nanoribbons
Computational Materials Science, cilt.273, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 273
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.commatsci.2026.114975
- Dergi Adı: Computational Materials Science
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Applied Science & Technology Source, Chimica, Compendex, INSPEC, Academic Search Ultimate (EBSCO), Engineering Source (EBSCO)
- Anahtar Kelimeler: 7-armchair graphene nanoribbon, Chemical functionalization, DFT–NEGF, Electronic band structure, Negative differential resistance (NDR), Quantum transport
- Sivas Cumhuriyet Üniversitesi Adresli: Evet
Özet
Chemical modification offers a flexible approach to modifying the electronic characteristics and coherent quantum transmission properties of semiconducting graphene nanoribbons. In this study, density functional theory (DFT) combined with the non-equilibrium Green's function (NEGF) formalism was employed to investigate pristine hydrogen-passivated 7-armchair graphene nanoribbons (7-AGNRs) and systems functionalized with –NH2, –OH, –CH3, -F, -Cl, -Br, –CF3, –CN, and –NO2 groups. Within a consistent computational framework, analyses were performed on electronic band structures, zero- and finite-bias transmission spectra, projected local density of states, and current–voltage characteristics. The pristine 7-AGNR displays a direct Γ–Γ band gap of 1.65 eV, whereas functionalization results in a reduced gap of 1.15–1.45 eV, without changing its direct-gap nature. OH- and NH2-functionalized systems result in the greatest decrease of the band gap, producing gaps of 1.15 and 1.26 eV, respectively. The system with NH2 functionalization shows the highest current, around 10−15 A, while pristine 7-AGNR exhibits an effectively negligible response, around 10−20 A. The transport response is not determined solely by band gap narrowing, but is also influenced by energy locations, spatial distributions, and the transport probabilities of the available states. Specifically, the NO2-functionalized system exhibits a remarkable nonlinear I-V response and possesses a continuous negative differential resistance (NDR) region ranging from 0.5 to 0.8 V with a peak-to-valley current ratio of 2.64. The results obtained show that the selection of substituents facilitates the systematic control of the electronic and finite bias transport properties of 7-AGNRs.