Volatile biomarker detection using metal-decorated silicon nanowires for environmental and biomedical applications: A DFT study

• Silicon nanowires (SiNWs) can adsorb volatile biomarkers (VBs) • Adsorption of VBs on SiNWs is enhanced by Ag and Cu adatoms. • Short recovery times of metal-decorated SiNWs are ideal for VBs’ real-time sensing. • CO 2 and H 2 O influence adsorption energies of VBs and recovery times of SiNWs. • SiNWs have significant potential for real-time sensing uses in medical and environmental fields. The potential utilization of silicon nanowires (SiNWs) for detecting volatile biomarkers (VBs) was investigated through Density Functional Theory (DFT) calculations. Six VBs—2-propenal, 1-propanol, benzene, isoprene, methylcyclopentane, and styrene—were selected due to their relevance in medical diagnostics and environmental monitoring. The adsorption of these molecules on non-decorated and metal-decorated hydrogen-passivated SiNWs (Ag, Au, and Cu) was analyzed by calculating adsorption energies, electronic properties, work functions (WF), and recovery times (RT). The results show that SiNWs adsorb VBs, with adsorption energies exceeding 0.4 eV, indicating strong interactions between them. Non-decorated SiNWs exhibit the highest adsorption energy for 2-propenal, while metal adatoms enhance VB adsorption in some cases. The adsorption of 2-propenal on non-decorated SiNWs induces N-type behavior, whereas metal decoration with Ag and Cu entails the SiNWs to exhibit P-type behavior. Also, metal-decorated SiNWs show recovery times in the range of milliseconds. Moreover, the presence of CO 2 and H 2 O molecules present in exhaled breath, modify adsorption energies and recovery times, highlighting the influence of environmental factors on sensor performance. Overall, SiNWs show great promise as sensors for VBs, with applications in real-time medical diagnostics and environmental monitoring.