<p>Lung cancer is one of the most prevalent types of cancer found in humans, with the second-highest mortality rate. Early detection of this cancer can provide us with better chances of saving valuable lives. In the present work, we have theoretically investigated the adsorption mechanism of four volatile organic compounds (VOCs) present in the exhaled gases of lung cancer patients—C₆H₆, C₈H₈, C₅H₈, and C₆H₁₂&#xa0;on a proposed promising Pd-doped gallium arsenide (GaAs)-based gas sensor development for the early diagnosis of lung cancer. For analyzing different physicochemical properties, all the calculations have been performed using density functional theory (DFT) with B3LYP-D3 hybrid functional with LanL2DZ basis set for noncovalent interactions among the sensory systems and VOCs. We have observed that the Pd-doped gallium arsenide clusters have shown&#xa0;a better adsorption capability (12–67% improved adsorption process for the same VOCs) than the pristine cluster with higher adsorption energies. Also, other property analyses, such as the HOMO–LUMO energy gap and DOS spectrum analysis, confirm that Pd-doped GaAs nanoclusters could be potential materials for developing sensors to detect the volatile organic compounds from the breath of patients with lung cancer in the early stage.</p> Graphical Abstract <p></p>