**Abstract**

Nanomaterials integration in biosensors designs are known to enhance sensing and signaling capabilities by exhibiting remarkably high surface area enhancement and intrinsic reactivity owing to their distinctive optical, chemical, electrical and catalytic properties. We present the synthesis and characterization of silver nanoparticles (AgNPs), and their immobilization on a silicon on-chip biosensor platform to enhance sensing capability for prostate specific antigen (PSA) - cancer biomarkers. Several techniques, including UV-Visible (UV-Vis) absorption spectrum, Fourier transforms infrared spectroscopy (FTIR), high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM) and field emission scanning electron microscopy (FESEM) were used for characterizing the AgNPs. The biochemical sensor consists of AgNPs immobilized on the receptor layer of a silicon avalanche mode light emitting device (Si AM LED) which enables on-chip optical detection biological analytes. A bio-interaction layer etched from the chip interacts with the evanescent field of a micro dimensioned waveguide. An array of detectors below the receptor cavity selectively monitor reflected light in the UV, visible, infrared and far infrared wavelength regions. AgNPs used as an immobilization layer in the receptor layer enhances selective absorption analytes, causing a change in detection signal as a function of propagation wavelength as light is dispersed. The analytes could range from gases to cancer biomarkers like prostate specific antigen.

**Keywords:** silicon avalanche mode LED, silver nanoparticles, biochemical sensors, optical sensor, nanomaterials, receptor technology
