Band gap engineering in penta-graphene by substitutional doping: first-principles calculations

Date: 25 August 2016

Venue: UAntwerpen, Campus Groenenborger, Room U.247 - Groenenborgerlaan 171 - 2020 Antwerpen (route: UAntwerpen, Campus Groenenborger)

Time: 11:00 AM - 12:00 PM

Organization / co-organization: Condensed Matter Theory

Short description: CMT seminar presented by Dr Golibjon Berdiyorov


Penta-graphene (PG) – a pentagonal arrangement of carbon atoms with the Cairo tiling pattern – has received a lot of interest in recent years [1].

This is because PG is expected to be a potential candidate for broad applications in optoelectronics due to its intriguing properties, such as mechanical strength and wide electronic band gap. However, utilization of the full potential of PG for practical applications requires fundamental understanding of its structural, electronic and optical properties. In particular, the development of PG-based multi-functional optoelectronic devices strongly depends on the possibility of tuning the band gap of the material. Here, we use first-principles density functional theory (DFT) calculations to explore electronic structure of functionalized (with H, F, and OH) and substitutionally doped (with N, B, and Si) PG. We show that doping can be used as an effective tool to tune the band gap of the material over a wide energy range (0.8 eV – 4.3 eV). However, the value of the band gap depends on the type and location of the dopants.

For example, the strongest reduction of the band gap is obtained for Si substitutions on the top (bottom) plane of PG, whereas the substitution in the middle plane of PG has a minor effect on the band gap of the material. Surface functionalization always results in an increase of the band gap. Recent first-principles calculations indicate the possibility of creating stable two-dimensional materials consisting of pentagonal arrangement of carbon atoms and transition metals (penta-TiC2 ) [2] or metalloids (penta-SiC2) [3], which are isostructural to the penta-graphene. These hybrid materials exhibit enhanced electronic properties as compared to PG. However, utilization of the full potential of such low-dimensional materials for practical applications requires fundamental understanding of their structural, electronic, transport and optical properties. Here, we use DFT calculations to explore structural, electronic transport and optical properties of these hybrid materials in their pristine form and functionalized with foreign atoms.

1. S. Zhang, J. Zhou, Q. Wang, X. Chen, Y. Kawazoe, and P. Jena, PNAS, 112, 2372 (2015)
2. T. Zhao, S. Zhang, Y. Guo, and Q. Wang, Nanoscale 8, 233 (2016)
3. A. Lopez-Bezanilla and P. B. Littlewood, J. Phys. Chem. C, 119, 19469 (2015)

Condensed Matter theory seminar presented by Dr G.R. Berdiyorov from Qatar Environment and Energy Research Institute

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