Context <p>The impact of the combination of transition metals on the electronic, optical, magnetic, and I-V characteristics of GaP nanosheet was carried out by first-principles density functional theory (DFT) with nonequilibrium green’s function calculations. The band energy results of the GaP structure showed a semiconductor feature with a direct band gap of 1.29 eV. The electronic structures and the density of Ni- and Cu-doped states and (Ni-Cu) co-doped GaP were investigated. It exhibited that the impurity states are crucial in their impact on modifying the electronic properties of the system as the electron transfer rate can be enhanced. On the other hand, a pristine and Cu-doped GaP nanosheet represents a nonmagnetic semiconductor due to the polarized DOS in both spins’ directions displaying similarity. At the same time, the polarized DOS of Ni-doped GaP nanosheet displays a ferromagnetic phase. For (Ni-Cu) Co-doped GaP nanosheet, the resulting material shows the total density of states for both spin states is different and implies the presence of magnetic moments. The optical results showed that the Cu-doped GaP displays a shift in the absorption edge compared to pristine GaP. Also, the co-doped system displays a smoother absorption spectrum with reduced intensity in the peak region, indicating a combined effect of both dopants. The Ni-doped GaP displays the highest conductivity with the current reaching around ± 100,000 nA. This suggests that Ni has a more significant effect in enhancing charge transport.</p> Methods <p>Density functional theory (DFT) with a nonequilibrium green’s function approach was utilized to calculate the electronic, optical, magnetic, and I-V characteristics of the GaP nanosheet. The results of the electronic, optical, and magnetic properties were evaluated by applying the SIESTA package. I-V characteristics were evaluated by using the quantum transport code “GOLLUM.”</p>