Photoluminescence and I-V characteristics of a CdS-nanoparticles-porous-silicon heterojunction

Chemically capped CdS nanoparticles are embedded in porous silicon (PS) by a dip coating method. Atomic force microscopy measurements reveal that the PS surface is covered with CdS nanoparticles forming well-defined rectangul ar blocks of nearly uniform size (200 x 200 nm(2)). Photoelectron spectrosc opy and energy dispersive x-ray analysis confirm the presence of CdS in PS. Optical and electrical properties of the heterojunctions so-formed are inv estigated. Junction characteristics show that the composite so-formed exhib its very high forward current density (145 mA cm(-2)) and high reverse brea kdown voltage (15 V).