Photo-electrochemical etching with step- gradient illumination intensity was used to generate multi – porosity silicon quantum wire system (Q.W.Si) on n-type silicon wafer. A nano size photonic device of AL/Q.W.Si /si/AL was fabricated to investigate the electrical properties and the surface morphology with the aid of scanning electron microscopy. The J-V characteristics of (AL/Q.W.Si /AL) show a rectifying behavior with high ideality factor compared for single layer (Q.W.Si) devices with (AL/Q.W.Si /AL). The high value of ideality factor was explained based on the high density of the dangling bonds are found on the internal surface of the multi porosity layer, leading to poor electrical properties