Improving optical properties of wurtzite GaN with C and Fe co-doping: A DFT+U study

Density Functional Theory with Hubbard U parameter (DFT + U) was used to study the impact of C (6.25%) and Fe (12.5%) mono- and co-doping on wurtzite GaN, which modified the structural, electrical, magnetic, and optical properties. Under conditions of abundant N, the doping effect led to an increase in thermodynamic formability. For all the dopant combinations, a reduction in the band gap was seen. GaN becomes a ferrimagnetic material because of co-doping. The performance of the C and Fe co-doped GaN was the best due to the redshift of the absorption edge, which resulted in the improved absorption of near ultraviolet (UV) and visible-infrared (VIS-IR) photonic energies for both monodoping and co-doping structures. The doping caused an increase in the refractive index and dielectric constant. For C and Fe co-doped GaN, the maximum static dielectric constant and refractive index were 19.58 and 4.45, respectively. The findings of this work therefore point to the possible use of C, Fe mono- and co-doped GaN in UV, IR optoelectronic and photonic devices.