Question

Material Science

Select one new material being developed for emerging needs of technology. Describe why this material is suitable for this application. The reasons must be discussed in terms of the required properties and the ability to process(make) the material from raw material. Also discuss why the required properties are possible based on the atomic structure and bonding

Answer 1

One of the materials used extensively in todays day are semiconductors. They are used in most of the electronic devices like TV, computers, calculators, mobiles etc. These are a few examples we can't live without.

Before semiconductors, vacuum tubes were used which were bulky and expensive. Also they dissipated a large amount of heat. Their use is for the rectification and amplification of the current flow.

Semiconductors are those materials whose conductivity ranges between an insulator like glass and a conductor like metals. These materials include Silicon, Germanium, Gallium Arsenide and the like.

The Semiconductors must be able to conduct the electricity in one direction but block it in the opposite direction. This property is useful to convert the AC to DC signals.

The raw materials used to develop semiconductors include materials like Silicon. Now Silicon's conductivity falls in between a good conductor and an insulator. This property can be improved by adding elements like Boron, Arsenic, Phosphorus, Indium, etc. Now Silicon exists in the same structure as a diamond (FCC) The crystal structure of Silicon consists of a 34% packing density allowing for more substitution of imurities into the empty lattice points.

This process if substituting impurities is called as doping. Free holes are called p-type and free electrons are called n-type doping. As the charge carriers in the lattice increases the current flow in the lattice also increases.