The role of pulse time Toff on porous silicon as template for Au nanoparticles by using integrated electrochemical technique

In this work, we present technique known for its simplicity and low processing cost for the synthesis of novel nanostructure of various metals by means filling pores of porous silicon (PSi) with Au nanoparticles (AuNPs) via electrochemical deposition (ECD) method. PSi was prepared using pulsed anodic etching technique by using duration time,Tau 14 ms with varying pulse time, Toff at 2ms, 4ms and 6 ms at constant current density 10mA/cm2 for 30 minutes. In addition a sample that was etched with direct current (DC) method at constant current density at 10 mA/cm2 also prepared for comparison. After that, PSi was used as template for electrochemical deposition for AuNPs. The electrolyte for ECD was prepared by using AuNPs powder that was digested with aqua regia and diluted with deionized water using magnetic stirrer at 20°C for 15 minutes. Then, the deposition process was done using direct current at 1.5 mA/cm2 for lhour. Subsequently, the deposited samples underwent annealing process at 350° for 15 minutes to refine the structure by making it homogeneous. The porous structure has been confirmed by scanning electron microscopy (SEM). The energy-dispersive X-ray spectroscopy (EDX) pattern confirmed the existence of AuNPs formation with different sizes. We studied the photoluminescence (PL) properties of the PSi structure and the PL signal after gold deposition.