Multi-functional gallium arsenide nanoparticles and nanostructures fabricated using picosecond laser ablation

• Simultaneous fabrication of GaAs nanoparticles (NPs) and nanostructures (NSs) in a single run experiment (i.e., using picosecond pulsed laser ablation in three different liquids such as distilled water, ethanol, and polyvinyl alcohol). • Non-linear optical properties are analysed and a clear two photon absorption is noticed for GaAs NPs in the colloidal form. • Multifunctional applications are verified for the GaAs NSs formed. • All the produced GaAs NSs have antireflective nature, hydrophobic nature (For GaAs NSs produced in DW, ethanol) and hydrophilic nature (For GaAs NSs produced in Polyvinyl alcohol). • These structures upon coating with a thin layer of gold acts as SERS substrates for detecting a pesticide (Thiram) and a dye molecule (Malachite Green) with excellent reproducibility and reusability. GaAs based nanomaterials have attracted significant attention owing to their applications in electronic, photonic, and sensing devices. In the present communication, we report on the simultaneous fabrication of GaAs nanoparticles (NPs) and nanostructures (NSs) in a single experiment achieved using picosecond pulsed laser ablation in liquids along with the demonstration of their versatile multifunctional applications. GaAs substrates are ablated in three different liquids of distilled water (DW), ethanol, and polyvinyl alcohol (PVA). The morphology and compositions of the synthesized NPs and NSs are analysed using various characterization techniques. Optical and nonlinear optical (NLO) studies are carried out for these NPs in the colloidal form which demonstrated the presence of two-photon absorption. Further, the ablated GaAs substrates exhibited quasi-periodic surface structures with wide angle anti-reflection property and hydrophobic nature. These NSs with a thin layer of gold acted as surface-enhanced Raman scattering (SERS) substrates for detecting trace level hazardous materials such as thiram (a pesticide molecule) and malachite green (a dye molecule). Furthermore, these NSs provided superior Raman enhancements with excellent reproducibility and reusability thereby evidencing their versatility. Collectively, this work reveals quite a few possible multifunctional applications of the laser ablation products of GaAs (NPs and NSs).