Microbial synthesis of semiconductor CdS nanoparticles, their characterization, and their use in the fabrication of an ideal diode.

Cadmium sulfide nanoparticles were synthesized intracellularly by a Schizosaccharomyces pombe strain when challenged with 1 mM cadmium in solution. The nanoparticles, a known semiconducting material, exhibited an absorbance maximum at 305 nm. X-ray scattering data showed that the nanoparticles had a Wurtzite (Cd(16)S(20))-type hexagonal lattice structure and most of the nanoparicles were in the size range of 1-1.5 nm. The nanoparticles were used in the fabrication of a heterojunction with poly (p-phenylenevinylene). The diode exhibited approximately 75 mA/cm(2) current at 10 V when forward biased and the breakdown occurred at approximately 15 V in the reverse biased mode. These characteristics are considered ideal for a diode.