Adsorption and sensing characteristics of 2D GaN/MoS2 heterostructure towards biomolecules: atomistic insights from electronic structures

This study provides a novel and extensive first-principles analysis of the adsorption and sensing properties of the 2D gallium/molybdenum-based compounds heterojunction surface towards nucleobases and aromatic amino acid molecules. Using density functional theory (DFT), we have examined the interactions between the heterojunction and biomolecules. The calculated adsorption energies highlight a clear sequence of interaction strength among the nucleobases (G > C > A > T > U), indicating the heterojunction potential for selective DNA sequencing. Among the amino acids, Tyr demonstrates the strongest interaction with the surface, as evidenced by its high adsorption energy and substantial decrease in the work function. These effects are associated with an n-type doping behavior, confirmed by charge density difference and work function analysis. Additionally, significant spectral shifts in the electron energy loss spectra upon biomolecule adsorption further validate the heterostructure’s sensitivity. Overall, the 2D GaN/MoS 2 heterojunction demonstrates a strong potential as a selective, high-performance biosensing candidate for nucleobase and amino acid molecules detection.