Role of Doped Semiconductors in the Catalytic Activity

There are several substances in today’s world that are neither good conductors (metals) nor insulators (glass). At normal temperature, semiconductors are described as materials with a crystalline structure and very few free electrons. Examples of semiconductor include Silicon, carbon, germanium etc. At room temperature, the semiconductors act like an insulator with its resistivity which lies between that of conductor and insulator and most importantly, the conductivity can be controlled by addition of various impurities. Mostly, the semiconducting materials are crystalline in nature with rarely found semiconductor in form of amorphous and liquid. The electronic industries across the globe includes transistors, solar cells, light-emitting diodes (LEDs), and digital and analog integrated circuits are dependent on semiconductor technology. The diverse property of the semiconductor materials lies at the quantum level which includes the motions of the building blocks like electrons and holes in the crystal and lattice. Electrical conductivity being opposite to that of a metal and its conductivity can be tailored by adding impurities commonly known as doping or by applying different mechanism like electrical fields or lights. Conductivities in semiconductors are due to movement of free electron (n-type) and holes (p-type) and are sensitive to temperature, illumination, magnetic field and impurity atoms introduced. Controlling the concentration and location of p- and n-type dopant under a precise condition is utmost important for electronic devices.