Doped Semiconductor

Nano powders are doped with different ions such as Al, In, Ga, etc. have improved electrical, optical, and catalytic properties. Among these, Al-doped ZnO nanopowders are both conductive and transparent in the visible region and thus can be utilized in transparent conductive pastes.

ZnO is an n-type semiconductor with wide direct band gap energy (3.37 eV) and a larger binding energy (60 meV). Due to its unique characteristics like low cost, non toxicity, abundance in nature, suitability to doping, this material has got wide applications in electronic and optoelectronic devices such as ultraviolet light-emitters, piezoelectric transducers and solar cells.

The sensitive dependence of a semiconductor's properties on dopants has provided an extensive range of tunable phenomena to explore and apply to devices. It is possible to identify the effects of solitary dopants on commercial device performance as well as on the fundamental properties of a semiconductor material. New applications have become available that require the discrete character of a single dopants, such as single-spin devices in the area of quantum information or single-dopants transistors.

Conductive polymers can be doped by adding chemical reactants to oxidize, or sometimes reduce, the system so that electrons are pushed into the conducting orbitals within the already potentially conducting system. There are two primary methods of doping a conductive polymer, both of which use an oxidation-reduction (i.e., redox) process.

Chemical doping involves exposing a polymer such as melanin, typically a thin film, to an oxidant such as iodine or bromine. Alternatively, the polymer can be exposed to a reductant; this method is far less common, and typically involves alkali metals. Electrochemical doping involves suspending a polymer-coated, working electrode in an electrolyte solution in which the polymer is insoluble along with separate counter and reference electrodes. An electric potential difference is created between the electrodes that cause a charge and the appropriate counter ion from the electrolyte to enter the polymer in the form of electron addition (i.e., n-doping) or removal (i.e., p-doping).