New Innovative Nano Sized Metallic Semi-Conductor

Feb. 11, 2013 - PRLog -- Indian researchers have developed a new metallic semiconductor. The group, based at Centre for Research and Post Graduate Department of Physics, Ayya Nadar Janaki Ammal College comments: “To our best knowledge, this is the first demonstration of semiconducting nature of lead nanopowder (Pb). So far, lead metal has been known as a good / super conductor.” The researchers have explained the synthesis procedures of this metal powder in their earlier report [Theivasanthi et al, arXiv:1212.5795 (http://arxiv.org/abs/1212.5795)] and explore its semiconducting properties in current report [Theivasanthi et al, arXiv:1302.1456 (http://arxiv.org/abs/1302.1456)]. Findings of this study suggests that the synthesized material is an efficient semiconducting material and can be utilized for making solar cells, optoelectronic, power and other semiconductor devices. TEM image of spherical Pb Nanoparticles is in Fig.1. This work throws some light on and helps further research on nano-sized lead powder.

It is a well known fact that generally nano-materials have behaviors different from their bulk material. Size and shape provides important control over many of the physical properties (viz., melting point, magnetism, specific heat, conductivity, band gap, etc.), luminescence, optical, chemical and catalytic properties of nanomaterials. The present research has been done, based on these facts and the new nano sized Pb metallic semiconductor has been innovated. Photoluminescence study of the material indicates the emission of photon and suggests presence of bandgap in the material. This confirms semiconducting properties. PL spectra are in Fig.2 & 3.

As a direct bandgap material, the visible light shining on its surface is well absorbed by this material. Also, the large surface area (314 nm2) and high specific surface area (52m2g-1) of this material augments its light absorbance property. Quantum yield value greater than 1 of this material is the result of the gain of energy and it shows possible utilization for heat or photochemical reaction or photo-induced or radiation-induced chain reactions, in which a single photon may trigger a long chain of transformations. These characters will be very useful while applying this semiconductor material in photovoltaic cells.

The researchers have studied band gap values of Pb nanopowder obtained from UV-Vis, PL, Cyclic voltammetry analyses and resistivity values from Four probe analyses results. “Our data clearly indicates the semiconducting nature of Pb nanopowder and its direct bandgap,” the researchers comment, adding: “Further research related to electrical behaviors, battery performances etc. of this material are going on.”

This research has been published in arXiv of Cornell University.

http://arxiv.org/abs/1302.1456  ,   http://arxiv.org/abs/1212.5795