Doping and co-doping as optical engineering tools for Graphene

Graphene’s exceptional carrier mobility and broadband optical transparency make it an attractive platform for optoelectronic applications; however, its zero bandgap and nearly uniform absorption of ~2.3% across the visible spectrum limit its direct use in photonic devices. Doping and co-doping strategies have recently emerged as powerful tools for optical engineering of graphene, enabling controlled modification of its electronic structure and optical response. Substitutional doping with heteroatoms such as boron, nitrogen, or sulfur can shift the Fermi level, introduce mid-gap states, and enhance light absorption in selected spectral regions, thereby overcoming the limitations of pristine graphene. Co-doping, which combines two or more dopants, further refines this effect by synergistically balancing charge redistribution, strain fields, and defect states, often resulting in improved stability and tunability compared to single-dopant systems. First-principles calculations, particularly those implemented in Materials Studio, have been extensively applied to explore these mechanisms by predicting changes in dielectric functions, absorption spectra, and plasmonic behavior under varying dopant concentrations and configurations. Such studies demonstrate that doping and co-doping not only enable bandgap engineering but also facilitate red- or blue-shifts in absorption edges, enhance excitonic effects, and introduce tunable plasmon resonances. Collectively, these approaches establish chemical doping and co-doping as versatile and reliable methods for tailoring graphene’s optical properties, providing design pathways for advanced photodetectors, modulators, and sensing devices.

Dr. Deepa Sharma is a theoretical physicist with expertise in computational nano-physics. Her research work is focused upon simulation and modelling of carbon nanomaterials and calculation of their electronic, spectroscopic and optical properties using Density Functional Theory and Tight Binding Model. Her expertise extends across Condensed Matter Physics, Spectroscopy, Optics, Electronics, Superconductivity and Material Sciences. Her recent theoretical prediction of the possibility of proximity induced superconductivity in single-walled carbon nanotubes has proven to be path-breaking. She is serving as an Associate Professor of Physics in Department of Higher Education, Haryana (India) and is currently posted at Shaheed Udham Singh Government College, Matak-Majri (Haryana) India.