Synthesis of Au:TiO2 Nanoparticles via Laser Ablation in Liquid Deposited on Porous-Si for Improved Spectral Responsivity

Abstract

In this study, Au:TiO2 nanoparticles (NPs) are prepared by using the laser ablation method in liquid at different laser energies (600, 800, and1000 mJ). After that, Au: TiO2 NPs were deposited on porous-Si(PS). Porous silicon (PS) is synthesized by using the photoelectrochemical etching (PECE) of n-type crystalline Si (c-Si) wafers of (100) orientation. The intensity of the etching current density was (4, 12, and 20 mA/cm 2 ), with 16% (HF), and the etching time was 15 minutes. The X-ray diffraction (XRD) techniques, scanning electron microscopy (SEM), UV-visible spectrophotometry, and electrical properties are used to characterize the obtained particles. From the photo-detector measurements, the spectral responsivity curves three inclusive regions; the first peak was due to the absorption of UV light by Au: TiO2 NPs. The second peak was corresponding to the visible light absorption with the PS layer and the third peak was due to the absorption edge of the Si substrate. The higher responsivity of Au: TiO2 NPs/PS photo-detector was found to be 2.56A/W for specimens prepared at laser energy 800mJ.